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START-INFO-DIR-ENTRY
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File: gdb.info, Node: Architecture-Specific Protocol Details, Next: Tracepoint Packets, Prev: General Query Packets, Up: Remote Protocol
E.5 Architecture-Specific Protocol Details
==========================================
This section describes how the remote protocol is applied to specific
target architectures. Also see *note Standard Target Features::, for
details of XML target descriptions for each architecture.
* Menu:
* ARM-Specific Protocol Details::
* MIPS-Specific Protocol Details::

File: gdb.info, Node: ARM-Specific Protocol Details, Next: MIPS-Specific Protocol Details, Up: Architecture-Specific Protocol Details
E.5.1 ARM-specific Protocol Details
-----------------------------------
* Menu:
* ARM Breakpoint Kinds::

File: gdb.info, Node: ARM Breakpoint Kinds, Up: ARM-Specific Protocol Details
E.5.1.1 ARM Breakpoint Kinds
............................
These breakpoint kinds are defined for the 'Z0' and 'Z1' packets.
2
16-bit Thumb mode breakpoint.
3
32-bit Thumb mode (Thumb-2) breakpoint.
4
32-bit ARM mode breakpoint.

File: gdb.info, Node: MIPS-Specific Protocol Details, Prev: ARM-Specific Protocol Details, Up: Architecture-Specific Protocol Details
E.5.2 MIPS-specific Protocol Details
------------------------------------
* Menu:
* MIPS Register packet Format::
* MIPS Breakpoint Kinds::

File: gdb.info, Node: MIPS Register packet Format, Next: MIPS Breakpoint Kinds, Up: MIPS-Specific Protocol Details
E.5.2.1 MIPS Register Packet Format
...................................
The following 'g'/'G' packets have previously been defined. In the
below, some thirty-two bit registers are transferred as sixty-four bits.
Those registers should be zero/sign extended (which?) to fill the space
allocated. Register bytes are transferred in target byte order. The
two nibbles within a register byte are transferred most-significant -
least-significant.
MIPS32
All registers are transferred as thirty-two bit quantities in the
order: 32 general-purpose; sr; lo; hi; bad; cause; pc; 32
floating-point registers; fsr; fir; fp.
MIPS64
All registers are transferred as sixty-four bit quantities
(including thirty-two bit registers such as 'sr'). The ordering is
the same as 'MIPS32'.

File: gdb.info, Node: MIPS Breakpoint Kinds, Prev: MIPS Register packet Format, Up: MIPS-Specific Protocol Details
E.5.2.2 MIPS Breakpoint Kinds
.............................
These breakpoint kinds are defined for the 'Z0' and 'Z1' packets.
2
16-bit MIPS16 mode breakpoint.
3
16-bit microMIPS mode breakpoint.
4
32-bit standard MIPS mode breakpoint.
5
32-bit microMIPS mode breakpoint.

File: gdb.info, Node: Tracepoint Packets, Next: Host I/O Packets, Prev: Architecture-Specific Protocol Details, Up: Remote Protocol
E.6 Tracepoint Packets
======================
Here we describe the packets GDB uses to implement tracepoints (*note
Tracepoints::).
'QTDP:N:ADDR:ENA:STEP:PASS[:FFLEN][:XLEN,BYTES][-]'
Create a new tracepoint, number N, at ADDR. If ENA is 'E', then
the tracepoint is enabled; if it is 'D', then the tracepoint is
disabled. The STEP gives the tracepoint's step count, and PASS
gives its pass count. If an 'F' is present, then the tracepoint is
to be a fast tracepoint, and the FLEN is the number of bytes that
the target should copy elsewhere to make room for the tracepoint.
If an 'X' is present, it introduces a tracepoint condition, which
consists of a hexadecimal length, followed by a comma and
hex-encoded bytes, in a manner similar to action encodings as
described below. If the trailing '-' is present, further 'QTDP'
packets will follow to specify this tracepoint's actions.
Replies:
'OK'
The packet was understood and carried out.
'qRelocInsn'
*Note Relocate instruction reply packet: Tracepoint Packets.
''
The packet was not recognized.
'QTDP:-N:ADDR:[S]ACTION...[-]'
Define actions to be taken when a tracepoint is hit. The N and
ADDR must be the same as in the initial 'QTDP' packet for this
tracepoint. This packet may only be sent immediately after another
'QTDP' packet that ended with a '-'. If the trailing '-' is
present, further 'QTDP' packets will follow, specifying more
actions for this tracepoint.
In the series of action packets for a given tracepoint, at most one
can have an 'S' before its first ACTION. If such a packet is sent,
it and the following packets define "while-stepping" actions. Any
prior packets define ordinary actions -- that is, those taken when
the tracepoint is first hit. If no action packet has an 'S', then
all the packets in the series specify ordinary tracepoint actions.
The 'ACTION...' portion of the packet is a series of actions,
concatenated without separators. Each action has one of the
following forms:
'R MASK'
Collect the registers whose bits are set in MASK, a
hexadecimal number whose I'th bit is set if register number I
should be collected. (The least significant bit is numbered
zero.) Note that MASK may be any number of digits long; it
may not fit in a 32-bit word.
'M BASEREG,OFFSET,LEN'
Collect LEN bytes of memory starting at the address in
register number BASEREG, plus OFFSET. If BASEREG is '-1',
then the range has a fixed address: OFFSET is the address of
the lowest byte to collect. The BASEREG, OFFSET, and LEN
parameters are all unsigned hexadecimal values (the '-1' value
for BASEREG is a special case).
'X LEN,EXPR'
Evaluate EXPR, whose length is LEN, and collect memory as it
directs. The agent expression EXPR is as described in *note
Agent Expressions::. Each byte of the expression is encoded
as a two-digit hex number in the packet; LEN is the number of
bytes in the expression (and thus one-half the number of hex
digits in the packet).
Any number of actions may be packed together in a single 'QTDP'
packet, as long as the packet does not exceed the maximum packet
length (400 bytes, for many stubs). There may be only one 'R'
action per tracepoint, and it must precede any 'M' or 'X' actions.
Any registers referred to by 'M' and 'X' actions must be collected
by a preceding 'R' action. (The "while-stepping" actions are
treated as if they were attached to a separate tracepoint, as far
as these restrictions are concerned.)
Replies:
'OK'
The packet was understood and carried out.
'qRelocInsn'
*Note Relocate instruction reply packet: Tracepoint Packets.
''
The packet was not recognized.
'QTDPsrc:N:ADDR:TYPE:START:SLEN:BYTES'
Specify a source string of tracepoint N at address ADDR. This is
useful to get accurate reproduction of the tracepoints originally
downloaded at the beginning of the trace run. The TYPE is the name
of the tracepoint part, such as 'cond' for the tracepoint's
conditional expression (see below for a list of types), while BYTES
is the string, encoded in hexadecimal.
START is the offset of the BYTES within the overall source string,
while SLEN is the total length of the source string. This is
intended for handling source strings that are longer than will fit
in a single packet.
The available string types are 'at' for the location, 'cond' for
the conditional, and 'cmd' for an action command. GDB sends a
separate packet for each command in the action list, in the same
order in which the commands are stored in the list.
The target does not need to do anything with source strings except
report them back as part of the replies to the 'qTfP'/'qTsP' query
packets.
Although this packet is optional, and GDB will only send it if the
target replies with 'TracepointSource' *Note General Query
Packets::, it makes both disconnected tracing and trace files much
easier to use. Otherwise the user must be careful that the
tracepoints in effect while looking at trace frames are identical
to the ones in effect during the trace run; even a small
discrepancy could cause 'tdump' not to work, or a particular trace
frame not be found.
'QTDV:N:VALUE:BUILTIN:NAME'
Create a new trace state variable, number N, with an initial value
of VALUE, which is a 64-bit signed integer. Both N and VALUE are
encoded as hexadecimal values. GDB has the option of not using
this packet for initial values of zero; the target should simply
create the trace state variables as they are mentioned in
expressions. The value BUILTIN should be 1 (one) if the trace
state variable is builtin and 0 (zero) if it is not builtin. GDB
only sets BUILTIN to 1 if a previous 'qTfV' or 'qTsV' packet had it
set. The contents of NAME is the hex-encoded name (without the
leading '$') of the trace state variable.
'QTFrame:N'
Select the N'th tracepoint frame from the buffer, and use the
register and memory contents recorded there to answer subsequent
request packets from GDB.
A successful reply from the stub indicates that the stub has found
the requested frame. The response is a series of parts,
concatenated without separators, describing the frame we selected.
Each part has one of the following forms:
'F F'
The selected frame is number N in the trace frame buffer; F is
a hexadecimal number. If F is '-1', then there was no frame
matching the criteria in the request packet.
'T T'
The selected trace frame records a hit of tracepoint number T;
T is a hexadecimal number.
'QTFrame:pc:ADDR'
Like 'QTFrame:N', but select the first tracepoint frame after the
currently selected frame whose PC is ADDR; ADDR is a hexadecimal
number.
'QTFrame:tdp:T'
Like 'QTFrame:N', but select the first tracepoint frame after the
currently selected frame that is a hit of tracepoint T; T is a
hexadecimal number.
'QTFrame:range:START:END'
Like 'QTFrame:N', but select the first tracepoint frame after the
currently selected frame whose PC is between START (inclusive) and
END (inclusive); START and END are hexadecimal numbers.
'QTFrame:outside:START:END'
Like 'QTFrame:range:START:END', but select the first frame
_outside_ the given range of addresses (exclusive).
'qTMinFTPILen'
This packet requests the minimum length of instruction at which a
fast tracepoint (*note Set Tracepoints::) may be placed. For
instance, on the 32-bit x86 architecture, it is possible to use a
4-byte jump, but it depends on the target system being able to
create trampolines in the first 64K of memory, which might or might
not be possible for that system. So the reply to this packet will
be 4 if it is able to arrange for that.
Replies:
'0'
The minimum instruction length is currently unknown.
'LENGTH'
The minimum instruction length is LENGTH, where LENGTH is a
hexadecimal number greater or equal to 1. A reply of 1 means
that a fast tracepoint may be placed on any instruction
regardless of size.
'E'
An error has occurred.
''
An empty reply indicates that the request is not supported by
the stub.
'QTStart'
Begin the tracepoint experiment. Begin collecting data from
tracepoint hits in the trace frame buffer. This packet supports
the 'qRelocInsn' reply (*note Relocate instruction reply packet:
Tracepoint Packets.).
'QTStop'
End the tracepoint experiment. Stop collecting trace frames.
'QTEnable:N:ADDR'
Enable tracepoint N at address ADDR in a started tracepoint
experiment. If the tracepoint was previously disabled, then
collection of data from it will resume.
'QTDisable:N:ADDR'
Disable tracepoint N at address ADDR in a started tracepoint
experiment. No more data will be collected from the tracepoint
unless 'QTEnable:N:ADDR' is subsequently issued.
'QTinit'
Clear the table of tracepoints, and empty the trace frame buffer.
'QTro:START1,END1:START2,END2:...'
Establish the given ranges of memory as "transparent". The stub
will answer requests for these ranges from memory's current
contents, if they were not collected as part of the tracepoint hit.
GDB uses this to mark read-only regions of memory, like those
containing program code. Since these areas never change, they
should still have the same contents they did when the tracepoint
was hit, so there's no reason for the stub to refuse to provide
their contents.
'QTDisconnected:VALUE'
Set the choice to what to do with the tracing run when GDB
disconnects from the target. A VALUE of 1 directs the target to
continue the tracing run, while 0 tells the target to stop tracing
if GDB is no longer in the picture.
'qTStatus'
Ask the stub if there is a trace experiment running right now.
The reply has the form:
'TRUNNING[;FIELD]...'
RUNNING is a single digit '1' if the trace is presently
running, or '0' if not. It is followed by semicolon-separated
optional fields that an agent may use to report additional
status.
If the trace is not running, the agent may report any of several
explanations as one of the optional fields:
'tnotrun:0'
No trace has been run yet.
'tstop[:TEXT]:0'
The trace was stopped by a user-originated stop command. The
optional TEXT field is a user-supplied string supplied as part
of the stop command (for instance, an explanation of why the
trace was stopped manually). It is hex-encoded.
'tfull:0'
The trace stopped because the trace buffer filled up.
'tdisconnected:0'
The trace stopped because GDB disconnected from the target.
'tpasscount:TPNUM'
The trace stopped because tracepoint TPNUM exceeded its pass
count.
'terror:TEXT:TPNUM'
The trace stopped because tracepoint TPNUM had an error. The
string TEXT is available to describe the nature of the error
(for instance, a divide by zero in the condition expression);
it is hex encoded.
'tunknown:0'
The trace stopped for some other reason.
Additional optional fields supply statistical and other
information. Although not required, they are extremely useful for
users monitoring the progress of a trace run. If a trace has
stopped, and these numbers are reported, they must reflect the
state of the just-stopped trace.
'tframes:N'
The number of trace frames in the buffer.
'tcreated:N'
The total number of trace frames created during the run. This
may be larger than the trace frame count, if the buffer is
circular.
'tsize:N'
The total size of the trace buffer, in bytes.
'tfree:N'
The number of bytes still unused in the buffer.
'circular:N'
The value of the circular trace buffer flag. '1' means that
the trace buffer is circular and old trace frames will be
discarded if necessary to make room, '0' means that the trace
buffer is linear and may fill up.
'disconn:N'
The value of the disconnected tracing flag. '1' means that
tracing will continue after GDB disconnects, '0' means that
the trace run will stop.
'qTP:TP:ADDR'
Ask the stub for the current state of tracepoint number TP at
address ADDR.
Replies:
'VHITS:USAGE'
The tracepoint has been hit HITS times so far during the trace
run, and accounts for USAGE in the trace buffer. Note that
'while-stepping' steps are not counted as separate hits, but
the steps' space consumption is added into the usage number.
'qTV:VAR'
Ask the stub for the value of the trace state variable number VAR.
Replies:
'VVALUE'
The value of the variable is VALUE. This will be the current
value of the variable if the user is examining a running
target, or a saved value if the variable was collected in the
trace frame that the user is looking at. Note that multiple
requests may result in different reply values, such as when
requesting values while the program is running.
'U'
The value of the variable is unknown. This would occur, for
example, if the user is examining a trace frame in which the
requested variable was not collected.
'qTfP'
'qTsP'
These packets request data about tracepoints that are being used by
the target. GDB sends 'qTfP' to get the first piece of data, and
multiple 'qTsP' to get additional pieces. Replies to these packets
generally take the form of the 'QTDP' packets that define
tracepoints. (FIXME add detailed syntax)
'qTfV'
'qTsV'
These packets request data about trace state variables that are on
the target. GDB sends 'qTfV' to get the first vari of data, and
multiple 'qTsV' to get additional variables. Replies to these
packets follow the syntax of the 'QTDV' packets that define trace
state variables.
'qTfSTM'
'qTsSTM'
These packets request data about static tracepoint markers that
exist in the target program. GDB sends 'qTfSTM' to get the first
piece of data, and multiple 'qTsSTM' to get additional pieces.
Replies to these packets take the following form:
Reply:
'm ADDRESS:ID:EXTRA'
A single marker
'm ADDRESS:ID:EXTRA,ADDRESS:ID:EXTRA...'
a comma-separated list of markers
'l'
(lower case letter 'L') denotes end of list.
'E NN'
An error occurred. The error number NN is given as hex
digits.
''
An empty reply indicates that the request is not supported by
the stub.
The ADDRESS is encoded in hex; ID and EXTRA are strings encoded in
hex.
In response to each query, the target will reply with a list of one
or more markers, separated by commas. GDB will respond to each
reply with a request for more markers (using the 'qs' form of the
query), until the target responds with 'l' (lower-case ell, for
"last").
'qTSTMat:ADDRESS'
This packets requests data about static tracepoint markers in the
target program at ADDRESS. Replies to this packet follow the
syntax of the 'qTfSTM' and 'qTsSTM' packets that list static
tracepoint markers.
'QTSave:FILENAME'
This packet directs the target to save trace data to the file name
FILENAME in the target's filesystem. The FILENAME is encoded as a
hex string; the interpretation of the file name (relative vs
absolute, wild cards, etc) is up to the target.
'qTBuffer:OFFSET,LEN'
Return up to LEN bytes of the current contents of trace buffer,
starting at OFFSET. The trace buffer is treated as if it were a
contiguous collection of traceframes, as per the trace file format.
The reply consists as many hex-encoded bytes as the target can
deliver in a packet; it is not an error to return fewer than were
asked for. A reply consisting of just 'l' indicates that no bytes
are available.
'QTBuffer:circular:VALUE'
This packet directs the target to use a circular trace buffer if
VALUE is 1, or a linear buffer if the value is 0.
'QTBuffer:size:SIZE'
This packet directs the target to make the trace buffer be of size
SIZE if possible. A value of '-1' tells the target to use whatever
size it prefers.
'QTNotes:[TYPE:TEXT][;TYPE:TEXT]...'
This packet adds optional textual notes to the trace run.
Allowable types include 'user', 'notes', and 'tstop', the TEXT
fields are arbitrary strings, hex-encoded.
E.6.1 Relocate instruction reply packet
---------------------------------------
When installing fast tracepoints in memory, the target may need to
relocate the instruction currently at the tracepoint address to a
different address in memory. For most instructions, a simple copy is
enough, but, for example, call instructions that implicitly push the
return address on the stack, and relative branches or other PC-relative
instructions require offset adjustment, so that the effect of executing
the instruction at a different address is the same as if it had executed
in the original location.
In response to several of the tracepoint packets, the target may also
respond with a number of intermediate 'qRelocInsn' request packets
before the final result packet, to have GDB handle this relocation
operation. If a packet supports this mechanism, its documentation will
explicitly say so. See for example the above descriptions for the
'QTStart' and 'QTDP' packets. The format of the request is:
'qRelocInsn:FROM;TO'
This requests GDB to copy instruction at address FROM to address
TO, possibly adjusted so that executing the instruction at TO has
the same effect as executing it at FROM. GDB writes the adjusted
instruction to target memory starting at TO.
Replies:
'qRelocInsn:ADJUSTED_SIZE'
Informs the stub the relocation is complete. The ADJUSTED_SIZE is
the length in bytes of resulting relocated instruction sequence.
'E NN'
A badly formed request was detected, or an error was encountered
while relocating the instruction.

File: gdb.info, Node: Host I/O Packets, Next: Interrupts, Prev: Tracepoint Packets, Up: Remote Protocol
E.7 Host I/O Packets
====================
The "Host I/O" packets allow GDB to perform I/O operations on the far
side of a remote link. For example, Host I/O is used to upload and
download files to a remote target with its own filesystem. Host I/O
uses the same constant values and data structure layout as the
target-initiated File-I/O protocol. However, the Host I/O packets are
structured differently. The target-initiated protocol relies on target
memory to store parameters and buffers. Host I/O requests are initiated
by GDB, and the target's memory is not involved. *Note File-I/O Remote
Protocol Extension::, for more details on the target-initiated protocol.
The Host I/O request packets all encode a single operation along with
its arguments. They have this format:
'vFile:OPERATION: PARAMETER...'
OPERATION is the name of the particular request; the target should
compare the entire packet name up to the second colon when checking
for a supported operation. The format of PARAMETER depends on the
operation. Numbers are always passed in hexadecimal. Negative
numbers have an explicit minus sign (i.e. two's complement is not
used). Strings (e.g. filenames) are encoded as a series of
hexadecimal bytes. The last argument to a system call may be a
buffer of escaped binary data (*note Binary Data::).
The valid responses to Host I/O packets are:
'F RESULT [, ERRNO] [; ATTACHMENT]'
RESULT is the integer value returned by this operation, usually
non-negative for success and -1 for errors. If an error has
occured, ERRNO will be included in the result specifying a value
defined by the File-I/O protocol (*note Errno Values::). For
operations which return data, ATTACHMENT supplies the data as a
binary buffer. Binary buffers in response packets are escaped in
the normal way (*note Binary Data::). See the individual packet
documentation for the interpretation of RESULT and ATTACHMENT.
''
An empty response indicates that this operation is not recognized.
These are the supported Host I/O operations:
'vFile:open: FILENAME, FLAGS, MODE'
Open a file at FILENAME and return a file descriptor for it, or
return -1 if an error occurs. The FILENAME is a string, FLAGS is
an integer indicating a mask of open flags (*note Open Flags::),
and MODE is an integer indicating a mask of mode bits to use if the
file is created (*note mode_t Values::). *Note open::, for details
of the open flags and mode values.
'vFile:close: FD'
Close the open file corresponding to FD and return 0, or -1 if an
error occurs.
'vFile:pread: FD, COUNT, OFFSET'
Read data from the open file corresponding to FD. Up to COUNT
bytes will be read from the file, starting at OFFSET relative to
the start of the file. The target may read fewer bytes; common
reasons include packet size limits and an end-of-file condition.
The number of bytes read is returned. Zero should only be returned
for a successful read at the end of the file, or if COUNT was zero.
The data read should be returned as a binary attachment on success.
If zero bytes were read, the response should include an empty
binary attachment (i.e. a trailing semicolon). The return value is
the number of target bytes read; the binary attachment may be
longer if some characters were escaped.
'vFile:pwrite: FD, OFFSET, DATA'
Write DATA (a binary buffer) to the open file corresponding to FD.
Start the write at OFFSET from the start of the file. Unlike many
'write' system calls, there is no separate COUNT argument; the
length of DATA in the packet is used. 'vFile:pwrite' returns the
number of bytes written, which may be shorter than the length of
DATA, or -1 if an error occurred.
'vFile:fstat: FD'
Get information about the open file corresponding to FD. On
success the information is returned as a binary attachment and the
return value is the size of this attachment in bytes. If an error
occurs the return value is -1. The format of the returned binary
attachment is as described in *note struct stat::.
'vFile:unlink: FILENAME'
Delete the file at FILENAME on the target. Return 0, or -1 if an
error occurs. The FILENAME is a string.
'vFile:readlink: FILENAME'
Read value of symbolic link FILENAME on the target. Return the
number of bytes read, or -1 if an error occurs.
The data read should be returned as a binary attachment on success.
If zero bytes were read, the response should include an empty
binary attachment (i.e. a trailing semicolon). The return value is
the number of target bytes read; the binary attachment may be
longer if some characters were escaped.
'vFile:setfs: PID'
Select the filesystem on which 'vFile' operations with FILENAME
arguments will operate. This is required for GDB to be able to
access files on remote targets where the remote stub does not share
a common filesystem with the inferior(s).
If PID is nonzero, select the filesystem as seen by process PID.
If PID is zero, select the filesystem as seen by the remote stub.
Return 0 on success, or -1 if an error occurs. If 'vFile:setfs:'
indicates success, the selected filesystem remains selected until
the next successful 'vFile:setfs:' operation.

File: gdb.info, Node: Interrupts, Next: Notification Packets, Prev: Host I/O Packets, Up: Remote Protocol
E.8 Interrupts
==============
In all-stop mode, when a program on the remote target is running, GDB
may attempt to interrupt it by sending a 'Ctrl-C', 'BREAK' or a 'BREAK'
followed by 'g', control of which is specified via GDB's
'interrupt-sequence'.
The precise meaning of 'BREAK' is defined by the transport mechanism
and may, in fact, be undefined. GDB does not currently define a 'BREAK'
mechanism for any of the network interfaces except for TCP, in which
case GDB sends the 'telnet' BREAK sequence.
'Ctrl-C', on the other hand, is defined and implemented for all
transport mechanisms. It is represented by sending the single byte
'0x03' without any of the usual packet overhead described in the
Overview section (*note Overview::). When a '0x03' byte is transmitted
as part of a packet, it is considered to be packet data and does _not_
represent an interrupt. E.g., an 'X' packet (*note X packet::), used
for binary downloads, may include an unescaped '0x03' as part of its
packet.
'BREAK' followed by 'g' is also known as Magic SysRq g. When Linux
kernel receives this sequence from serial port, it stops execution and
connects to gdb.
In non-stop mode, because packet resumptions are asynchronous (*note
vCont packet::), GDB is always free to send a remote command to the
remote stub, even when the target is running. For that reason, GDB
instead sends a regular packet (*note vCtrlC packet::) with the usual
packet framing instead of the single byte '0x03'.
Stubs are not required to recognize these interrupt mechanisms and
the precise meaning associated with receipt of the interrupt is
implementation defined. If the target supports debugging of multiple
threads and/or processes, it should attempt to interrupt all
currently-executing threads and processes. If the stub is successful at
interrupting the running program, it should send one of the stop reply
packets (*note Stop Reply Packets::) to GDB as a result of successfully
stopping the program in all-stop mode, and a stop reply for each stopped
thread in non-stop mode. Interrupts received while the program is
stopped are queued and the program will be interrupted when it is
resumed next time.

File: gdb.info, Node: Notification Packets, Next: Remote Non-Stop, Prev: Interrupts, Up: Remote Protocol
E.9 Notification Packets
========================
The GDB remote serial protocol includes "notifications", packets that
require no acknowledgment. Both the GDB and the stub may send
notifications (although the only notifications defined at present are
sent by the stub). Notifications carry information without incurring
the round-trip latency of an acknowledgment, and so are useful for
low-impact communications where occasional packet loss is not a problem.
A notification packet has the form '% DATA # CHECKSUM', where DATA is
the content of the notification, and CHECKSUM is a checksum of DATA,
computed and formatted as for ordinary GDB packets. A notification's
DATA never contains '$', '%' or '#' characters. Upon receiving a
notification, the recipient sends no '+' or '-' to acknowledge the
notification's receipt or to report its corruption.
Every notification's DATA begins with a name, which contains no colon
characters, followed by a colon character.
Recipients should silently ignore corrupted notifications and
notifications they do not understand. Recipients should restart timeout
periods on receipt of a well-formed notification, whether or not they
understand it.
Senders should only send the notifications described here when this
protocol description specifies that they are permitted. In the future,
we may extend the protocol to permit existing notifications in new
contexts; this rule helps older senders avoid confusing newer
recipients.
(Older versions of GDB ignore bytes received until they see the '$'
byte that begins an ordinary packet, so new stubs may transmit
notifications without fear of confusing older clients. There are no
notifications defined for GDB to send at the moment, but we assume that
most older stubs would ignore them, as well.)
Each notification is comprised of three parts:
'NAME:EVENT'
The notification packet is sent by the side that initiates the
exchange (currently, only the stub does that), with EVENT carrying
the specific information about the notification, and NAME
specifying the name of the notification.
'ACK'
The acknowledge sent by the other side, usually GDB, to acknowledge
the exchange and request the event.
The purpose of an asynchronous notification mechanism is to report to
GDB that something interesting happened in the remote stub.
The remote stub may send notification NAME:EVENT at any time, but GDB
acknowledges the notification when appropriate. The notification event
is pending before GDB acknowledges. Only one notification at a time may
be pending; if additional events occur before GDB has acknowledged the
previous notification, they must be queued by the stub for later
synchronous transmission in response to ACK packets from GDB. Because
the notification mechanism is unreliable, the stub is permitted to
resend a notification if it believes GDB may not have received it.
Specifically, notifications may appear when GDB is not otherwise
reading input from the stub, or when GDB is expecting to read a normal
synchronous response or a '+'/'-' acknowledgment to a packet it has
sent. Notification packets are distinct from any other communication
from the stub so there is no ambiguity.
After receiving a notification, GDB shall acknowledge it by sending a
ACK packet as a regular, synchronous request to the stub. Such
acknowledgment is not required to happen immediately, as GDB is
permitted to send other, unrelated packets to the stub first, which the
stub should process normally.
Upon receiving a ACK packet, if the stub has other queued events to
report to GDB, it shall respond by sending a normal EVENT. GDB shall
then send another ACK packet to solicit further responses; again, it is
permitted to send other, unrelated packets as well which the stub should
process normally.
If the stub receives a ACK packet and there are no additional EVENT
to report, the stub shall return an 'OK' response. At this point, GDB
has finished processing a notification and the stub has completed
sending any queued events. GDB won't accept any new notifications until
the final 'OK' is received . If further notification events occur, the
stub shall send a new notification, GDB shall accept the notification,
and the process shall be repeated.
The process of asynchronous notification can be illustrated by the
following example:
<- %Stop:T0505:98e7ffbf;04:4ce6ffbf;08:b1b6e54c;thread:p7526.7526;core:0;
...
-> vStopped
<- T0505:68f37db7;04:40f37db7;08:63850408;thread:p7526.7528;core:0;
-> vStopped
<- T0505:68e3fdb6;04:40e3fdb6;08:63850408;thread:p7526.7529;core:0;
-> vStopped
<- OK
The following notifications are defined:
NotificationAck Event Description
Stop vStopped REPLY. The REPLY has the Report an asynchronous
form of a stop reply, as stop event in non-stop
described in mode.
*note Stop Reply Packets::.
Refer to
*note Remote Non-Stop::,
for information on how
these notifications are
acknowledged by GDB.

File: gdb.info, Node: Remote Non-Stop, Next: Packet Acknowledgment, Prev: Notification Packets, Up: Remote Protocol
E.10 Remote Protocol Support for Non-Stop Mode
==============================================
GDB's remote protocol supports non-stop debugging of multi-threaded
programs, as described in *note Non-Stop Mode::. If the stub supports
non-stop mode, it should report that to GDB by including 'QNonStop+' in
its 'qSupported' response (*note qSupported::).
GDB typically sends a 'QNonStop' packet only when establishing a new
connection with the stub. Entering non-stop mode does not alter the
state of any currently-running threads, but targets must stop all
threads in any already-attached processes when entering all-stop mode.
GDB uses the '?' packet as necessary to probe the target state after a
mode change.
In non-stop mode, when an attached process encounters an event that
would otherwise be reported with a stop reply, it uses the asynchronous
notification mechanism (*note Notification Packets::) to inform GDB. In
contrast to all-stop mode, where all threads in all processes are
stopped when a stop reply is sent, in non-stop mode only the thread
reporting the stop event is stopped. That is, when reporting a 'S' or
'T' response to indicate completion of a step operation, hitting a
breakpoint, or a fault, only the affected thread is stopped; any other
still-running threads continue to run. When reporting a 'W' or 'X'
response, all running threads belonging to other attached processes
continue to run.
In non-stop mode, the target shall respond to the '?' packet as
follows. First, any incomplete stop reply notification/'vStopped'
sequence in progress is abandoned. The target must begin a new sequence
reporting stop events for all stopped threads, whether or not it has
previously reported those events to GDB. The first stop reply is sent
as a synchronous reply to the '?' packet, and subsequent stop replies
are sent as responses to 'vStopped' packets using the mechanism
described above. The target must not send asynchronous stop reply
notifications until the sequence is complete. If all threads are
running when the target receives the '?' packet, or if the target is not
attached to any process, it shall respond 'OK'.
If the stub supports non-stop mode, it should also support the
'swbreak' stop reason if software breakpoints are supported, and the
'hwbreak' stop reason if hardware breakpoints are supported (*note
swbreak stop reason::). This is because given the asynchronous nature
of non-stop mode, between the time a thread hits a breakpoint and the
time the event is finally processed by GDB, the breakpoint may have
already been removed from the target. Due to this, GDB needs to be able
to tell whether a trap stop was caused by a delayed breakpoint event,
which should be ignored, as opposed to a random trap signal, which
should be reported to the user. Note the 'swbreak' feature implies that
the target is responsible for adjusting the PC when a software
breakpoint triggers, if necessary, such as on the x86 architecture.

File: gdb.info, Node: Packet Acknowledgment, Next: Examples, Prev: Remote Non-Stop, Up: Remote Protocol
E.11 Packet Acknowledgment
==========================
By default, when either the host or the target machine receives a
packet, the first response expected is an acknowledgment: either '+' (to
indicate the package was received correctly) or '-' (to request
retransmission). This mechanism allows the GDB remote protocol to
operate over unreliable transport mechanisms, such as a serial line.
In cases where the transport mechanism is itself reliable (such as a
pipe or TCP connection), the '+'/'-' acknowledgments are redundant. It
may be desirable to disable them in that case to reduce communication
overhead, or for other reasons. This can be accomplished by means of
the 'QStartNoAckMode' packet; *note QStartNoAckMode::.
When in no-acknowledgment mode, neither the stub nor GDB shall send
or expect '+'/'-' protocol acknowledgments. The packet and response
format still includes the normal checksum, as described in *note
Overview::, but the checksum may be ignored by the receiver.
If the stub supports 'QStartNoAckMode' and prefers to operate in
no-acknowledgment mode, it should report that to GDB by including
'QStartNoAckMode+' in its response to 'qSupported'; *note qSupported::.
If GDB also supports 'QStartNoAckMode' and it has not been disabled via
the 'set remote noack-packet off' command (*note Remote
Configuration::), GDB may then send a 'QStartNoAckMode' packet to the
stub. Only then may the stub actually turn off packet acknowledgments.
GDB sends a final '+' acknowledgment of the stub's 'OK' response, which
can be safely ignored by the stub.
Note that 'set remote noack-packet' command only affects negotiation
between GDB and the stub when subsequent connections are made; it does
not affect the protocol acknowledgment state for any current connection.
Since '+'/'-' acknowledgments are enabled by default when a new
connection is established, there is also no protocol request to
re-enable the acknowledgments for the current connection, once disabled.

File: gdb.info, Node: Examples, Next: File-I/O Remote Protocol Extension, Prev: Packet Acknowledgment, Up: Remote Protocol
E.12 Examples
=============
Example sequence of a target being re-started. Notice how the restart
does not get any direct output:
-> R00
<- +
_target restarts_
-> ?
<- +
<- T001:1234123412341234
-> +
Example sequence of a target being stepped by a single instruction:
-> G1445...
<- +
-> s
<- +
_time passes_
<- T001:1234123412341234
-> +
-> g
<- +
<- 1455...
-> +

File: gdb.info, Node: File-I/O Remote Protocol Extension, Next: Library List Format, Prev: Examples, Up: Remote Protocol
E.13 File-I/O Remote Protocol Extension
=======================================
* Menu:
* File-I/O Overview::
* Protocol Basics::
* The F Request Packet::
* The F Reply Packet::
* The Ctrl-C Message::
* Console I/O::
* List of Supported Calls::
* Protocol-specific Representation of Datatypes::
* Constants::
* File-I/O Examples::

File: gdb.info, Node: File-I/O Overview, Next: Protocol Basics, Up: File-I/O Remote Protocol Extension
E.13.1 File-I/O Overview
------------------------
The "File I/O remote protocol extension" (short: File-I/O) allows the
target to use the host's file system and console I/O to perform various
system calls. System calls on the target system are translated into a
remote protocol packet to the host system, which then performs the
needed actions and returns a response packet to the target system. This
simulates file system operations even on targets that lack file systems.
The protocol is defined to be independent of both the host and target
systems. It uses its own internal representation of datatypes and
values. Both GDB and the target's GDB stub are responsible for
translating the system-dependent value representations into the internal
protocol representations when data is transmitted.
The communication is synchronous. A system call is possible only
when GDB is waiting for a response from the 'C', 'c', 'S' or 's'
packets. While GDB handles the request for a system call, the target is
stopped to allow deterministic access to the target's memory. Therefore
File-I/O is not interruptible by target signals. On the other hand, it
is possible to interrupt File-I/O by a user interrupt ('Ctrl-C') within
GDB.
The target's request to perform a host system call does not finish
the latest 'C', 'c', 'S' or 's' action. That means, after finishing the
system call, the target returns to continuing the previous activity
(continue, step). No additional continue or step request from GDB is
required.
(gdb) continue
<- target requests 'system call X'
target is stopped, GDB executes system call
-> GDB returns result
... target continues, GDB returns to wait for the target
<- target hits breakpoint and sends a Txx packet
The protocol only supports I/O on the console and to regular files on
the host file system. Character or block special devices, pipes, named
pipes, sockets or any other communication method on the host system are
not supported by this protocol.
File I/O is not supported in non-stop mode.

File: gdb.info, Node: Protocol Basics, Next: The F Request Packet, Prev: File-I/O Overview, Up: File-I/O Remote Protocol Extension
E.13.2 Protocol Basics
----------------------
The File-I/O protocol uses the 'F' packet as the request as well as
reply packet. Since a File-I/O system call can only occur when GDB is
waiting for a response from the continuing or stepping target, the
File-I/O request is a reply that GDB has to expect as a result of a
previous 'C', 'c', 'S' or 's' packet. This 'F' packet contains all
information needed to allow GDB to call the appropriate host system
call:
* A unique identifier for the requested system call.
* All parameters to the system call. Pointers are given as addresses
in the target memory address space. Pointers to strings are given
as pointer/length pair. Numerical values are given as they are.
Numerical control flags are given in a protocol-specific
representation.
At this point, GDB has to perform the following actions.
* If the parameters include pointer values to data needed as input to
a system call, GDB requests this data from the target with a
standard 'm' packet request. This additional communication has to
be expected by the target implementation and is handled as any
other 'm' packet.
* GDB translates all value from protocol representation to host
representation as needed. Datatypes are coerced into the host
types.
* GDB calls the system call.
* It then coerces datatypes back to protocol representation.
* If the system call is expected to return data in buffer space
specified by pointer parameters to the call, the data is
transmitted to the target using a 'M' or 'X' packet. This packet
has to be expected by the target implementation and is handled as
any other 'M' or 'X' packet.
Eventually GDB replies with another 'F' packet which contains all
necessary information for the target to continue. This at least
contains
* Return value.
* 'errno', if has been changed by the system call.
* "Ctrl-C" flag.
After having done the needed type and value coercion, the target
continues the latest continue or step action.

File: gdb.info, Node: The F Request Packet, Next: The F Reply Packet, Prev: Protocol Basics, Up: File-I/O Remote Protocol Extension
E.13.3 The 'F' Request Packet
-----------------------------
The 'F' request packet has the following format:
'FCALL-ID,PARAMETER...'
CALL-ID is the identifier to indicate the host system call to be
called. This is just the name of the function.
PARAMETER... are the parameters to the system call. Parameters are
hexadecimal integer values, either the actual values in case of
scalar datatypes, pointers to target buffer space in case of
compound datatypes and unspecified memory areas, or pointer/length
pairs in case of string parameters. These are appended to the
CALL-ID as a comma-delimited list. All values are transmitted in
ASCII string representation, pointer/length pairs separated by a
slash.

File: gdb.info, Node: The F Reply Packet, Next: The Ctrl-C Message, Prev: The F Request Packet, Up: File-I/O Remote Protocol Extension
E.13.4 The 'F' Reply Packet
---------------------------
The 'F' reply packet has the following format:
'FRETCODE,ERRNO,CTRL-C FLAG;CALL-SPECIFIC ATTACHMENT'
RETCODE is the return code of the system call as hexadecimal value.
ERRNO is the 'errno' set by the call, in protocol-specific
representation. This parameter can be omitted if the call was
successful.
CTRL-C FLAG is only sent if the user requested a break. In this
case, ERRNO must be sent as well, even if the call was successful.
The CTRL-C FLAG itself consists of the character 'C':
F0,0,C
or, if the call was interrupted before the host call has been
performed:
F-1,4,C
assuming 4 is the protocol-specific representation of 'EINTR'.

File: gdb.info, Node: The Ctrl-C Message, Next: Console I/O, Prev: The F Reply Packet, Up: File-I/O Remote Protocol Extension
E.13.5 The 'Ctrl-C' Message
---------------------------
If the 'Ctrl-C' flag is set in the GDB reply packet (*note The F Reply
Packet::), the target should behave as if it had gotten a break message.
The meaning for the target is "system call interrupted by 'SIGINT'".
Consequentially, the target should actually stop (as with a break
message) and return to GDB with a 'T02' packet.
It's important for the target to know in which state the system call
was interrupted. There are two possible cases:
* The system call hasn't been performed on the host yet.
* The system call on the host has been finished.
These two states can be distinguished by the target by the value of
the returned 'errno'. If it's the protocol representation of 'EINTR',
the system call hasn't been performed. This is equivalent to the
'EINTR' handling on POSIX systems. In any other case, the target may
presume that the system call has been finished -- successfully or not --
and should behave as if the break message arrived right after the system
call.
GDB must behave reliably. If the system call has not been called
yet, GDB may send the 'F' reply immediately, setting 'EINTR' as 'errno'
in the packet. If the system call on the host has been finished before
the user requests a break, the full action must be finished by GDB.
This requires sending 'M' or 'X' packets as necessary. The 'F' packet
may only be sent when either nothing has happened or the full action has
been completed.

File: gdb.info, Node: Console I/O, Next: List of Supported Calls, Prev: The Ctrl-C Message, Up: File-I/O Remote Protocol Extension
E.13.6 Console I/O
------------------
By default and if not explicitly closed by the target system, the file
descriptors 0, 1 and 2 are connected to the GDB console. Output on the
GDB console is handled as any other file output operation ('write(1,
...)' or 'write(2, ...)'). Console input is handled by GDB so that
after the target read request from file descriptor 0 all following
typing is buffered until either one of the following conditions is met:
* The user types 'Ctrl-c'. The behaviour is as explained above, and
the 'read' system call is treated as finished.
* The user presses <RET>. This is treated as end of input with a
trailing newline.
* The user types 'Ctrl-d'. This is treated as end of input. No
trailing character (neither newline nor 'Ctrl-D') is appended to
the input.
If the user has typed more characters than fit in the buffer given to
the 'read' call, the trailing characters are buffered in GDB until
either another 'read(0, ...)' is requested by the target, or debugging
is stopped at the user's request.

File: gdb.info, Node: List of Supported Calls, Next: Protocol-specific Representation of Datatypes, Prev: Console I/O, Up: File-I/O Remote Protocol Extension
E.13.7 List of Supported Calls
------------------------------
* Menu:
* open::
* close::
* read::
* write::
* lseek::
* rename::
* unlink::
* stat/fstat::
* gettimeofday::
* isatty::
* system::

File: gdb.info, Node: open, Next: close, Up: List of Supported Calls
open
....
Synopsis:
int open(const char *pathname, int flags);
int open(const char *pathname, int flags, mode_t mode);
Request:
'Fopen,PATHPTR/LEN,FLAGS,MODE'
FLAGS is the bitwise 'OR' of the following values:
'O_CREAT'
If the file does not exist it will be created. The host rules
apply as far as file ownership and time stamps are concerned.
'O_EXCL'
When used with 'O_CREAT', if the file already exists it is an
error and open() fails.
'O_TRUNC'
If the file already exists and the open mode allows writing
('O_RDWR' or 'O_WRONLY' is given) it will be truncated to zero
length.
'O_APPEND'
The file is opened in append mode.
'O_RDONLY'
The file is opened for reading only.
'O_WRONLY'
The file is opened for writing only.
'O_RDWR'
The file is opened for reading and writing.
Other bits are silently ignored.
MODE is the bitwise 'OR' of the following values:
'S_IRUSR'
User has read permission.
'S_IWUSR'
User has write permission.
'S_IRGRP'
Group has read permission.
'S_IWGRP'
Group has write permission.
'S_IROTH'
Others have read permission.
'S_IWOTH'
Others have write permission.
Other bits are silently ignored.
Return value:
'open' returns the new file descriptor or -1 if an error occurred.
Errors:
'EEXIST'
PATHNAME already exists and 'O_CREAT' and 'O_EXCL' were used.
'EISDIR'
PATHNAME refers to a directory.
'EACCES'
The requested access is not allowed.
'ENAMETOOLONG'
PATHNAME was too long.
'ENOENT'
A directory component in PATHNAME does not exist.
'ENODEV'
PATHNAME refers to a device, pipe, named pipe or socket.
'EROFS'
PATHNAME refers to a file on a read-only filesystem and write
access was requested.
'EFAULT'
PATHNAME is an invalid pointer value.
'ENOSPC'
No space on device to create the file.
'EMFILE'
The process already has the maximum number of files open.
'ENFILE'
The limit on the total number of files open on the system has
been reached.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: close, Next: read, Prev: open, Up: List of Supported Calls
close
.....
Synopsis:
int close(int fd);
Request:
'Fclose,FD'
Return value:
'close' returns zero on success, or -1 if an error occurred.
Errors:
'EBADF'
FD isn't a valid open file descriptor.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: read, Next: write, Prev: close, Up: List of Supported Calls
read
....
Synopsis:
int read(int fd, void *buf, unsigned int count);
Request:
'Fread,FD,BUFPTR,COUNT'
Return value:
On success, the number of bytes read is returned. Zero indicates
end of file. If count is zero, read returns zero as well. On
error, -1 is returned.
Errors:
'EBADF'
FD is not a valid file descriptor or is not open for reading.
'EFAULT'
BUFPTR is an invalid pointer value.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: write, Next: lseek, Prev: read, Up: List of Supported Calls
write
.....
Synopsis:
int write(int fd, const void *buf, unsigned int count);
Request:
'Fwrite,FD,BUFPTR,COUNT'
Return value:
On success, the number of bytes written are returned. Zero
indicates nothing was written. On error, -1 is returned.
Errors:
'EBADF'
FD is not a valid file descriptor or is not open for writing.
'EFAULT'
BUFPTR is an invalid pointer value.
'EFBIG'
An attempt was made to write a file that exceeds the
host-specific maximum file size allowed.
'ENOSPC'
No space on device to write the data.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: lseek, Next: rename, Prev: write, Up: List of Supported Calls
lseek
.....
Synopsis:
long lseek (int fd, long offset, int flag);
Request:
'Flseek,FD,OFFSET,FLAG'
FLAG is one of:
'SEEK_SET'
The offset is set to OFFSET bytes.
'SEEK_CUR'
The offset is set to its current location plus OFFSET bytes.
'SEEK_END'
The offset is set to the size of the file plus OFFSET bytes.
Return value:
On success, the resulting unsigned offset in bytes from the
beginning of the file is returned. Otherwise, a value of -1 is
returned.
Errors:
'EBADF'
FD is not a valid open file descriptor.
'ESPIPE'
FD is associated with the GDB console.
'EINVAL'
FLAG is not a proper value.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: rename, Next: unlink, Prev: lseek, Up: List of Supported Calls
rename
......
Synopsis:
int rename(const char *oldpath, const char *newpath);
Request:
'Frename,OLDPATHPTR/LEN,NEWPATHPTR/LEN'
Return value:
On success, zero is returned. On error, -1 is returned.
Errors:
'EISDIR'
NEWPATH is an existing directory, but OLDPATH is not a
directory.
'EEXIST'
NEWPATH is a non-empty directory.
'EBUSY'
OLDPATH or NEWPATH is a directory that is in use by some
process.
'EINVAL'
An attempt was made to make a directory a subdirectory of
itself.
'ENOTDIR'
A component used as a directory in OLDPATH or new path is not
a directory. Or OLDPATH is a directory and NEWPATH exists but
is not a directory.
'EFAULT'
OLDPATHPTR or NEWPATHPTR are invalid pointer values.
'EACCES'
No access to the file or the path of the file.
'ENAMETOOLONG'
OLDPATH or NEWPATH was too long.
'ENOENT'
A directory component in OLDPATH or NEWPATH does not exist.
'EROFS'
The file is on a read-only filesystem.
'ENOSPC'
The device containing the file has no room for the new
directory entry.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: unlink, Next: stat/fstat, Prev: rename, Up: List of Supported Calls
unlink
......
Synopsis:
int unlink(const char *pathname);
Request:
'Funlink,PATHNAMEPTR/LEN'
Return value:
On success, zero is returned. On error, -1 is returned.
Errors:
'EACCES'
No access to the file or the path of the file.
'EPERM'
The system does not allow unlinking of directories.
'EBUSY'
The file PATHNAME cannot be unlinked because it's being used
by another process.
'EFAULT'
PATHNAMEPTR is an invalid pointer value.
'ENAMETOOLONG'
PATHNAME was too long.
'ENOENT'
A directory component in PATHNAME does not exist.
'ENOTDIR'
A component of the path is not a directory.
'EROFS'
The file is on a read-only filesystem.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: stat/fstat, Next: gettimeofday, Prev: unlink, Up: List of Supported Calls
stat/fstat
..........
Synopsis:
int stat(const char *pathname, struct stat *buf);
int fstat(int fd, struct stat *buf);
Request:
'Fstat,PATHNAMEPTR/LEN,BUFPTR'
'Ffstat,FD,BUFPTR'
Return value:
On success, zero is returned. On error, -1 is returned.
Errors:
'EBADF'
FD is not a valid open file.
'ENOENT'
A directory component in PATHNAME does not exist or the path
is an empty string.
'ENOTDIR'
A component of the path is not a directory.
'EFAULT'
PATHNAMEPTR is an invalid pointer value.
'EACCES'
No access to the file or the path of the file.
'ENAMETOOLONG'
PATHNAME was too long.
'EINTR'
The call was interrupted by the user.

File: gdb.info, Node: gettimeofday, Next: isatty, Prev: stat/fstat, Up: List of Supported Calls
gettimeofday
............
Synopsis:
int gettimeofday(struct timeval *tv, void *tz);
Request:
'Fgettimeofday,TVPTR,TZPTR'
Return value:
On success, 0 is returned, -1 otherwise.
Errors:
'EINVAL'
TZ is a non-NULL pointer.
'EFAULT'
TVPTR and/or TZPTR is an invalid pointer value.

File: gdb.info, Node: isatty, Next: system, Prev: gettimeofday, Up: List of Supported Calls
isatty
......
Synopsis:
int isatty(int fd);
Request:
'Fisatty,FD'
Return value:
Returns 1 if FD refers to the GDB console, 0 otherwise.
Errors:
'EINTR'
The call was interrupted by the user.
Note that the 'isatty' call is treated as a special case: it returns
1 to the target if the file descriptor is attached to the GDB console, 0
otherwise. Implementing through system calls would require implementing
'ioctl' and would be more complex than needed.

File: gdb.info, Node: system, Prev: isatty, Up: List of Supported Calls
system
......
Synopsis:
int system(const char *command);
Request:
'Fsystem,COMMANDPTR/LEN'
Return value:
If LEN is zero, the return value indicates whether a shell is
available. A zero return value indicates a shell is not available.
For non-zero LEN, the value returned is -1 on error and the return
status of the command otherwise. Only the exit status of the
command is returned, which is extracted from the host's 'system'
return value by calling 'WEXITSTATUS(retval)'. In case '/bin/sh'
could not be executed, 127 is returned.
Errors:
'EINTR'
The call was interrupted by the user.
GDB takes over the full task of calling the necessary host calls to
perform the 'system' call. The return value of 'system' on the host is
simplified before it's returned to the target. Any termination signal
information from the child process is discarded, and the return value
consists entirely of the exit status of the called command.
Due to security concerns, the 'system' call is by default refused by
GDB. The user has to allow this call explicitly with the 'set remote
system-call-allowed 1' command.
'set remote system-call-allowed'
Control whether to allow the 'system' calls in the File I/O
protocol for the remote target. The default is zero (disabled).
'show remote system-call-allowed'
Show whether the 'system' calls are allowed in the File I/O
protocol.

File: gdb.info, Node: Protocol-specific Representation of Datatypes, Next: Constants, Prev: List of Supported Calls, Up: File-I/O Remote Protocol Extension
E.13.8 Protocol-specific Representation of Datatypes
----------------------------------------------------
* Menu:
* Integral Datatypes::
* Pointer Values::
* Memory Transfer::
* struct stat::
* struct timeval::

File: gdb.info, Node: Integral Datatypes, Next: Pointer Values, Up: Protocol-specific Representation of Datatypes
Integral Datatypes
..................
The integral datatypes used in the system calls are 'int', 'unsigned
int', 'long', 'unsigned long', 'mode_t', and 'time_t'.
'int', 'unsigned int', 'mode_t' and 'time_t' are implemented as 32
bit values in this protocol.
'long' and 'unsigned long' are implemented as 64 bit types.
*Note Limits::, for corresponding MIN and MAX values (similar to
those in 'limits.h') to allow range checking on host and target.
'time_t' datatypes are defined as seconds since the Epoch.
All integral datatypes transferred as part of a memory read or write
of a structured datatype e.g. a 'struct stat' have to be given in big
endian byte order.

File: gdb.info, Node: Pointer Values, Next: Memory Transfer, Prev: Integral Datatypes, Up: Protocol-specific Representation of Datatypes
Pointer Values
..............
Pointers to target data are transmitted as they are. An exception is
made for pointers to buffers for which the length isn't transmitted as
part of the function call, namely strings. Strings are transmitted as a
pointer/length pair, both as hex values, e.g.
1aaf/12
which is a pointer to data of length 18 bytes at position 0x1aaf. The
length is defined as the full string length in bytes, including the
trailing null byte. For example, the string '"hello world"' at address
0x123456 is transmitted as
123456/d

File: gdb.info, Node: Memory Transfer, Next: struct stat, Prev: Pointer Values, Up: Protocol-specific Representation of Datatypes
Memory Transfer
...............
Structured data which is transferred using a memory read or write (for
example, a 'struct stat') is expected to be in a protocol-specific
format with all scalar multibyte datatypes being big endian.
Translation to this representation needs to be done both by the target
before the 'F' packet is sent, and by GDB before it transfers memory to
the target. Transferred pointers to structured data should point to the
already-coerced data at any time.

File: gdb.info, Node: struct stat, Next: struct timeval, Prev: Memory Transfer, Up: Protocol-specific Representation of Datatypes
struct stat
...........
The buffer of type 'struct stat' used by the target and GDB is defined
as follows:
struct stat {
unsigned int st_dev; /* device */
unsigned int st_ino; /* inode */
mode_t st_mode; /* protection */
unsigned int st_nlink; /* number of hard links */
unsigned int st_uid; /* user ID of owner */
unsigned int st_gid; /* group ID of owner */
unsigned int st_rdev; /* device type (if inode device) */
unsigned long st_size; /* total size, in bytes */
unsigned long st_blksize; /* blocksize for filesystem I/O */
unsigned long st_blocks; /* number of blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last change */
};
The integral datatypes conform to the definitions given in the
appropriate section (see *note Integral Datatypes::, for details) so
this structure is of size 64 bytes.
The values of several fields have a restricted meaning and/or range
of values.
'st_dev'
A value of 0 represents a file, 1 the console.
'st_ino'
No valid meaning for the target. Transmitted unchanged.
'st_mode'
Valid mode bits are described in *note Constants::. Any other bits
have currently no meaning for the target.
'st_uid'
'st_gid'
'st_rdev'
No valid meaning for the target. Transmitted unchanged.
'st_atime'
'st_mtime'
'st_ctime'
These values have a host and file system dependent accuracy.
Especially on Windows hosts, the file system may not support exact
timing values.
The target gets a 'struct stat' of the above representation and is
responsible for coercing it to the target representation before
continuing.
Note that due to size differences between the host, target, and
protocol representations of 'struct stat' members, these members could
eventually get truncated on the target.

File: gdb.info, Node: struct timeval, Prev: struct stat, Up: Protocol-specific Representation of Datatypes
struct timeval
..............
The buffer of type 'struct timeval' used by the File-I/O protocol is
defined as follows:
struct timeval {
time_t tv_sec; /* second */
long tv_usec; /* microsecond */
};
The integral datatypes conform to the definitions given in the
appropriate section (see *note Integral Datatypes::, for details) so
this structure is of size 8 bytes.

File: gdb.info, Node: Constants, Next: File-I/O Examples, Prev: Protocol-specific Representation of Datatypes, Up: File-I/O Remote Protocol Extension
E.13.9 Constants
----------------
The following values are used for the constants inside of the protocol.
GDB and target are responsible for translating these values before and
after the call as needed.
* Menu:
* Open Flags::
* mode_t Values::
* Errno Values::
* Lseek Flags::
* Limits::

File: gdb.info, Node: Open Flags, Next: mode_t Values, Up: Constants
Open Flags
..........
All values are given in hexadecimal representation.
O_RDONLY 0x0
O_WRONLY 0x1
O_RDWR 0x2
O_APPEND 0x8
O_CREAT 0x200
O_TRUNC 0x400
O_EXCL 0x800

File: gdb.info, Node: mode_t Values, Next: Errno Values, Prev: Open Flags, Up: Constants
mode_t Values
.............
All values are given in octal representation.
S_IFREG 0100000
S_IFDIR 040000
S_IRUSR 0400
S_IWUSR 0200
S_IXUSR 0100
S_IRGRP 040
S_IWGRP 020
S_IXGRP 010
S_IROTH 04
S_IWOTH 02
S_IXOTH 01

File: gdb.info, Node: Errno Values, Next: Lseek Flags, Prev: mode_t Values, Up: Constants
Errno Values
............
All values are given in decimal representation.
EPERM 1
ENOENT 2
EINTR 4
EBADF 9
EACCES 13
EFAULT 14
EBUSY 16
EEXIST 17
ENODEV 19
ENOTDIR 20
EISDIR 21
EINVAL 22
ENFILE 23
EMFILE 24
EFBIG 27
ENOSPC 28
ESPIPE 29
EROFS 30
ENAMETOOLONG 91
EUNKNOWN 9999
'EUNKNOWN' is used as a fallback error value if a host system returns
any error value not in the list of supported error numbers.

File: gdb.info, Node: Lseek Flags, Next: Limits, Prev: Errno Values, Up: Constants
Lseek Flags
...........
SEEK_SET 0
SEEK_CUR 1
SEEK_END 2

File: gdb.info, Node: Limits, Prev: Lseek Flags, Up: Constants
Limits
......
All values are given in decimal representation.
INT_MIN -2147483648
INT_MAX 2147483647
UINT_MAX 4294967295
LONG_MIN -9223372036854775808
LONG_MAX 9223372036854775807
ULONG_MAX 18446744073709551615

File: gdb.info, Node: File-I/O Examples, Prev: Constants, Up: File-I/O Remote Protocol Extension
E.13.10 File-I/O Examples
-------------------------
Example sequence of a write call, file descriptor 3, buffer is at target
address 0x1234, 6 bytes should be written:
<- Fwrite,3,1234,6
_request memory read from target_
-> m1234,6
<- XXXXXX
_return "6 bytes written"_
-> F6
Example sequence of a read call, file descriptor 3, buffer is at
target address 0x1234, 6 bytes should be read:
<- Fread,3,1234,6
_request memory write to target_
-> X1234,6:XXXXXX
_return "6 bytes read"_
-> F6
Example sequence of a read call, call fails on the host due to
invalid file descriptor ('EBADF'):
<- Fread,3,1234,6
-> F-1,9
Example sequence of a read call, user presses 'Ctrl-c' before syscall
on host is called:
<- Fread,3,1234,6
-> F-1,4,C
<- T02
Example sequence of a read call, user presses 'Ctrl-c' after syscall
on host is called:
<- Fread,3,1234,6
-> X1234,6:XXXXXX
<- T02

File: gdb.info, Node: Library List Format, Next: Library List Format for SVR4 Targets, Prev: File-I/O Remote Protocol Extension, Up: Remote Protocol
E.14 Library List Format
========================
On some platforms, a dynamic loader (e.g. 'ld.so') runs in the same
process as your application to manage libraries. In this case, GDB can
use the loader's symbol table and normal memory operations to maintain a
list of shared libraries. On other platforms, the operating system
manages loaded libraries. GDB can not retrieve the list of currently
loaded libraries through memory operations, so it uses the
'qXfer:libraries:read' packet (*note qXfer library list read::) instead.
The remote stub queries the target's operating system and reports which
libraries are loaded.
The 'qXfer:libraries:read' packet returns an XML document which lists
loaded libraries and their offsets. Each library has an associated name
and one or more segment or section base addresses, which report where
the library was loaded in memory.
For the common case of libraries that are fully linked binaries, the
library should have a list of segments. If the target supports dynamic
linking of a relocatable object file, its library XML element should
instead include a list of allocated sections. The segment or section
bases are start addresses, not relocation offsets; they do not depend on
the library's link-time base addresses.
GDB must be linked with the Expat library to support XML library
lists. *Note Expat::.
A simple memory map, with one loaded library relocated by a single
offset, looks like this:
<library-list>
<library name="/lib/libc.so.6">
<segment address="0x10000000"/>
</library>
</library-list>
Another simple memory map, with one loaded library with three
allocated sections (.text, .data, .bss), looks like this:
<library-list>
<library name="sharedlib.o">
<section address="0x10000000"/>
<section address="0x20000000"/>
<section address="0x30000000"/>
</library>
</library-list>
The format of a library list is described by this DTD:
<!-- library-list: Root element with versioning -->
<!ELEMENT library-list (library)*>
<!ATTLIST library-list version CDATA #FIXED "1.0">
<!ELEMENT library (segment*, section*)>
<!ATTLIST library name CDATA #REQUIRED>
<!ELEMENT segment EMPTY>
<!ATTLIST segment address CDATA #REQUIRED>
<!ELEMENT section EMPTY>
<!ATTLIST section address CDATA #REQUIRED>
In addition, segments and section descriptors cannot be mixed within
a single library element, and you must supply at least one segment or
section for each library.

File: gdb.info, Node: Library List Format for SVR4 Targets, Next: Memory Map Format, Prev: Library List Format, Up: Remote Protocol
E.15 Library List Format for SVR4 Targets
=========================================
On SVR4 platforms GDB can use the symbol table of a dynamic loader (e.g.
'ld.so') and normal memory operations to maintain a list of shared
libraries. Still a special library list provided by this packet is more
efficient for the GDB remote protocol.
The 'qXfer:libraries-svr4:read' packet returns an XML document which
lists loaded libraries and their SVR4 linker parameters. For each
library on SVR4 target, the following parameters are reported:
- 'name', the absolute file name from the 'l_name' field of 'struct
link_map'.
- 'lm' with address of 'struct link_map' used for TLS (Thread Local
Storage) access.
- 'l_addr', the displacement as read from the field 'l_addr' of
'struct link_map'. For prelinked libraries this is not an absolute
memory address. It is a displacement of absolute memory address
against address the file was prelinked to during the library load.
- 'l_ld', which is memory address of the 'PT_DYNAMIC' segment
Additionally the single 'main-lm' attribute specifies address of
'struct link_map' used for the main executable. This parameter is used
for TLS access and its presence is optional.
GDB must be linked with the Expat library to support XML SVR4 library
lists. *Note Expat::.
A simple memory map, with two loaded libraries (which do not use
prelink), looks like this:
<library-list-svr4 version="1.0" main-lm="0xe4f8f8">
<library name="/lib/ld-linux.so.2" lm="0xe4f51c" l_addr="0xe2d000"
l_ld="0xe4eefc"/>
<library name="/lib/libc.so.6" lm="0xe4fbe8" l_addr="0x154000"
l_ld="0x152350"/>
</library-list-svr>
The format of an SVR4 library list is described by this DTD:
<!-- library-list-svr4: Root element with versioning -->
<!ELEMENT library-list-svr4 (library)*>
<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
<!ELEMENT library EMPTY>
<!ATTLIST library name CDATA #REQUIRED>
<!ATTLIST library lm CDATA #REQUIRED>
<!ATTLIST library l_addr CDATA #REQUIRED>
<!ATTLIST library l_ld CDATA #REQUIRED>

File: gdb.info, Node: Memory Map Format, Next: Thread List Format, Prev: Library List Format for SVR4 Targets, Up: Remote Protocol
E.16 Memory Map Format
======================
To be able to write into flash memory, GDB needs to obtain a memory map
from the target. This section describes the format of the memory map.
The memory map is obtained using the 'qXfer:memory-map:read' (*note
qXfer memory map read::) packet and is an XML document that lists memory
regions.
GDB must be linked with the Expat library to support XML memory maps.
*Note Expat::.
The top-level structure of the document is shown below:
<?xml version="1.0"?>
<!DOCTYPE memory-map
PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN"
"http://sourceware.org/gdb/gdb-memory-map.dtd">
<memory-map>
region...
</memory-map>
Each region can be either:
* A region of RAM starting at ADDR and extending for LENGTH bytes
from there:
<memory type="ram" start="ADDR" length="LENGTH"/>
* A region of read-only memory:
<memory type="rom" start="ADDR" length="LENGTH"/>
* A region of flash memory, with erasure blocks BLOCKSIZE bytes in
length:
<memory type="flash" start="ADDR" length="LENGTH">
<property name="blocksize">BLOCKSIZE</property>
</memory>
Regions must not overlap. GDB assumes that areas of memory not
covered by the memory map are RAM, and uses the ordinary 'M' and 'X'
packets to write to addresses in such ranges.
The formal DTD for memory map format is given below:
<!-- ................................................... -->
<!-- Memory Map XML DTD ................................ -->
<!-- File: memory-map.dtd .............................. -->
<!-- .................................... .............. -->
<!-- memory-map.dtd -->
<!-- memory-map: Root element with versioning -->
<!ELEMENT memory-map (memory)*>
<!ATTLIST memory-map version CDATA #FIXED "1.0.0">
<!ELEMENT memory (property)*>
<!-- memory: Specifies a memory region,
and its type, or device. -->
<!ATTLIST memory type (ram|rom|flash) #REQUIRED
start CDATA #REQUIRED
length CDATA #REQUIRED>
<!-- property: Generic attribute tag -->
<!ELEMENT property (#PCDATA | property)*>
<!ATTLIST property name (blocksize) #REQUIRED>

File: gdb.info, Node: Thread List Format, Next: Traceframe Info Format, Prev: Memory Map Format, Up: Remote Protocol
E.17 Thread List Format
=======================
To efficiently update the list of threads and their attributes, GDB
issues the 'qXfer:threads:read' packet (*note qXfer threads read::) and
obtains the XML document with the following structure:
<?xml version="1.0"?>
<threads>
<thread id="id" core="0" name="name">
... description ...
</thread>
</threads>
Each 'thread' element must have the 'id' attribute that identifies
the thread (*note thread-id syntax::). The 'core' attribute, if
present, specifies which processor core the thread was last executing
on. The 'name' attribute, if present, specifies the human-readable name
of the thread. The content of the of 'thread' element is interpreted as
human-readable auxiliary information. The 'handle' attribute, if
present, is a hex encoded representation of the thread handle.

File: gdb.info, Node: Traceframe Info Format, Next: Branch Trace Format, Prev: Thread List Format, Up: Remote Protocol
E.18 Traceframe Info Format
===========================
To be able to know which objects in the inferior can be examined when
inspecting a tracepoint hit, GDB needs to obtain the list of memory
ranges, registers and trace state variables that have been collected in
a traceframe.
This list is obtained using the 'qXfer:traceframe-info:read' (*note
qXfer traceframe info read::) packet and is an XML document.
GDB must be linked with the Expat library to support XML traceframe
info discovery. *Note Expat::.
The top-level structure of the document is shown below:
<?xml version="1.0"?>
<!DOCTYPE traceframe-info
PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN"
"http://sourceware.org/gdb/gdb-traceframe-info.dtd">
<traceframe-info>
block...
</traceframe-info>
Each traceframe block can be either:
* A region of collected memory starting at ADDR and extending for
LENGTH bytes from there:
<memory start="ADDR" length="LENGTH"/>
* A block indicating trace state variable numbered NUMBER has been
collected:
<tvar id="NUMBER"/>
The formal DTD for the traceframe info format is given below:
<!ELEMENT traceframe-info (memory | tvar)* >
<!ATTLIST traceframe-info version CDATA #FIXED "1.0">
<!ELEMENT memory EMPTY>
<!ATTLIST memory start CDATA #REQUIRED
length CDATA #REQUIRED>
<!ELEMENT tvar>
<!ATTLIST tvar id CDATA #REQUIRED>

File: gdb.info, Node: Branch Trace Format, Next: Branch Trace Configuration Format, Prev: Traceframe Info Format, Up: Remote Protocol
E.19 Branch Trace Format
========================
In order to display the branch trace of an inferior thread, GDB needs to
obtain the list of branches. This list is represented as list of
sequential code blocks that are connected via branches. The code in
each block has been executed sequentially.
This list is obtained using the 'qXfer:btrace:read' (*note qXfer
btrace read::) packet and is an XML document.
GDB must be linked with the Expat library to support XML traceframe
info discovery. *Note Expat::.
The top-level structure of the document is shown below:
<?xml version="1.0"?>
<!DOCTYPE btrace
PUBLIC "+//IDN gnu.org//DTD GDB Branch Trace V1.0//EN"
"http://sourceware.org/gdb/gdb-btrace.dtd">
<btrace>
block...
</btrace>
* A block of sequentially executed instructions starting at BEGIN and
ending at END:
<block begin="BEGIN" end="END"/>
The formal DTD for the branch trace format is given below:
<!ELEMENT btrace (block* | pt) >
<!ATTLIST btrace version CDATA #FIXED "1.0">
<!ELEMENT block EMPTY>
<!ATTLIST block begin CDATA #REQUIRED
end CDATA #REQUIRED>
<!ELEMENT pt (pt-config?, raw?)>
<!ELEMENT pt-config (cpu?)>
<!ELEMENT cpu EMPTY>
<!ATTLIST cpu vendor CDATA #REQUIRED
family CDATA #REQUIRED
model CDATA #REQUIRED
stepping CDATA #REQUIRED>
<!ELEMENT raw (#PCDATA)>

File: gdb.info, Node: Branch Trace Configuration Format, Prev: Branch Trace Format, Up: Remote Protocol
E.20 Branch Trace Configuration Format
======================================
For each inferior thread, GDB can obtain the branch trace configuration
using the 'qXfer:btrace-conf:read' (*note qXfer btrace-conf read::)
packet.
The configuration describes the branch trace format and configuration
settings for that format. The following information is described:
'bts'
This thread uses the "Branch Trace Store" (BTS) format.
'size'
The size of the BTS ring buffer in bytes.
'pt'
This thread uses the "Intel Processor Trace" (Intel PT) format.
'size'
The size of the Intel PT ring buffer in bytes.
GDB must be linked with the Expat library to support XML branch trace
configuration discovery. *Note Expat::.
The formal DTD for the branch trace configuration format is given
below:
<!ELEMENT btrace-conf (bts?, pt?)>
<!ATTLIST btrace-conf version CDATA #FIXED "1.0">
<!ELEMENT bts EMPTY>
<!ATTLIST bts size CDATA #IMPLIED>
<!ELEMENT pt EMPTY>
<!ATTLIST pt size CDATA #IMPLIED>

File: gdb.info, Node: Agent Expressions, Next: Target Descriptions, Prev: Remote Protocol, Up: Top
Appendix F The GDB Agent Expression Mechanism
*********************************************
In some applications, it is not feasible for the debugger to interrupt
the program's execution long enough for the developer to learn anything
helpful about its behavior. If the program's correctness depends on its
real-time behavior, delays introduced by a debugger might cause the
program to fail, even when the code itself is correct. It is useful to
be able to observe the program's behavior without interrupting it.
Using GDB's 'trace' and 'collect' commands, the user can specify
locations in the program, and arbitrary expressions to evaluate when
those locations are reached. Later, using the 'tfind' command, she can
examine the values those expressions had when the program hit the trace
points. The expressions may also denote objects in memory -- structures
or arrays, for example -- whose values GDB should record; while visiting
a particular tracepoint, the user may inspect those objects as if they
were in memory at that moment. However, because GDB records these
values without interacting with the user, it can do so quickly and
unobtrusively, hopefully not disturbing the program's behavior.
When GDB is debugging a remote target, the GDB "agent" code running
on the target computes the values of the expressions itself. To avoid
having a full symbolic expression evaluator on the agent, GDB translates
expressions in the source language into a simpler bytecode language, and
then sends the bytecode to the agent; the agent then executes the
bytecode, and records the values for GDB to retrieve later.
The bytecode language is simple; there are forty-odd opcodes, the
bulk of which are the usual vocabulary of C operands (addition,
subtraction, shifts, and so on) and various sizes of literals and memory
reference operations. The bytecode interpreter operates strictly on
machine-level values -- various sizes of integers and floating point
numbers -- and requires no information about types or symbols; thus, the
interpreter's internal data structures are simple, and each bytecode
requires only a few native machine instructions to implement it. The
interpreter is small, and strict limits on the memory and time required
to evaluate an expression are easy to determine, making it suitable for
use by the debugging agent in real-time applications.
* Menu:
* General Bytecode Design:: Overview of the interpreter.
* Bytecode Descriptions:: What each one does.
* Using Agent Expressions:: How agent expressions fit into the big picture.
* Varying Target Capabilities:: How to discover what the target can do.
* Rationale:: Why we did it this way.

File: gdb.info, Node: General Bytecode Design, Next: Bytecode Descriptions, Up: Agent Expressions
F.1 General Bytecode Design
===========================
The agent represents bytecode expressions as an array of bytes. Each
instruction is one byte long (thus the term "bytecode"). Some
instructions are followed by operand bytes; for example, the 'goto'
instruction is followed by a destination for the jump.
The bytecode interpreter is a stack-based machine; most instructions
pop their operands off the stack, perform some operation, and push the
result back on the stack for the next instruction to consume. Each
element of the stack may contain either a integer or a floating point
value; these values are as many bits wide as the largest integer that
can be directly manipulated in the source language. Stack elements
carry no record of their type; bytecode could push a value as an
integer, then pop it as a floating point value. However, GDB will not
generate code which does this. In C, one might define the type of a
stack element as follows:
union agent_val {
LONGEST l;
DOUBLEST d;
};
where 'LONGEST' and 'DOUBLEST' are 'typedef' names for the largest
integer and floating point types on the machine.
By the time the bytecode interpreter reaches the end of the
expression, the value of the expression should be the only value left on
the stack. For tracing applications, 'trace' bytecodes in the
expression will have recorded the necessary data, and the value on the
stack may be discarded. For other applications, like conditional
breakpoints, the value may be useful.
Separate from the stack, the interpreter has two registers:
'pc'
The address of the next bytecode to execute.
'start'
The address of the start of the bytecode expression, necessary for
interpreting the 'goto' and 'if_goto' instructions.
Neither of these registers is directly visible to the bytecode language
itself, but they are useful for defining the meanings of the bytecode
operations.
There are no instructions to perform side effects on the running
program, or call the program's functions; we assume that these
expressions are only used for unobtrusive debugging, not for patching
the running code.
Most bytecode instructions do not distinguish between the various
sizes of values, and operate on full-width values; the upper bits of the
values are simply ignored, since they do not usually make a difference
to the value computed. The exceptions to this rule are:
memory reference instructions ('ref'N)
There are distinct instructions to fetch different word sizes from
memory. Once on the stack, however, the values are treated as
full-size integers. They may need to be sign-extended; the 'ext'
instruction exists for this purpose.
the sign-extension instruction ('ext' N)
These clearly need to know which portion of their operand is to be
extended to occupy the full length of the word.
If the interpreter is unable to evaluate an expression completely for
some reason (a memory location is inaccessible, or a divisor is zero,
for example), we say that interpretation "terminates with an error".
This means that the problem is reported back to the interpreter's caller
in some helpful way. In general, code using agent expressions should
assume that they may attempt to divide by zero, fetch arbitrary memory
locations, and misbehave in other ways.
Even complicated C expressions compile to a few bytecode
instructions; for example, the expression 'x + y * z' would typically
produce code like the following, assuming that 'x' and 'y' live in
registers, and 'z' is a global variable holding a 32-bit 'int':
reg 1
reg 2
const32 address of z
ref32
ext 32
mul
add
end
In detail, these mean:
'reg 1'
Push the value of register 1 (presumably holding 'x') onto the
stack.
'reg 2'
Push the value of register 2 (holding 'y').
'const32 address of z'
Push the address of 'z' onto the stack.
'ref32'
Fetch a 32-bit word from the address at the top of the stack;
replace the address on the stack with the value. Thus, we replace
the address of 'z' with 'z''s value.
'ext 32'
Sign-extend the value on the top of the stack from 32 bits to full
length. This is necessary because 'z' is a signed integer.
'mul'
Pop the top two numbers on the stack, multiply them, and push their
product. Now the top of the stack contains the value of the
expression 'y * z'.
'add'
Pop the top two numbers, add them, and push the sum. Now the top
of the stack contains the value of 'x + y * z'.
'end'
Stop executing; the value left on the stack top is the value to be
recorded.

File: gdb.info, Node: Bytecode Descriptions, Next: Using Agent Expressions, Prev: General Bytecode Design, Up: Agent Expressions
F.2 Bytecode Descriptions
=========================
Each bytecode description has the following form:
'add' (0x02): A B => A+B
Pop the top two stack items, A and B, as integers; push their sum,
as an integer.
In this example, 'add' is the name of the bytecode, and '(0x02)' is
the one-byte value used to encode the bytecode, in hexadecimal. The
phrase "A B => A+B" shows the stack before and after the bytecode
executes. Beforehand, the stack must contain at least two values, A and
B; since the top of the stack is to the right, B is on the top of the
stack, and A is underneath it. After execution, the bytecode will have
popped A and B from the stack, and replaced them with a single value,
A+B. There may be other values on the stack below those shown, but the
bytecode affects only those shown.
Here is another example:
'const8' (0x22) N: => N
Push the 8-bit integer constant N on the stack, without sign
extension.
In this example, the bytecode 'const8' takes an operand N directly
from the bytecode stream; the operand follows the 'const8' bytecode
itself. We write any such operands immediately after the name of the
bytecode, before the colon, and describe the exact encoding of the
operand in the bytecode stream in the body of the bytecode description.
For the 'const8' bytecode, there are no stack items given before the
=>; this simply means that the bytecode consumes no values from the
stack. If a bytecode consumes no values, or produces no values, the
list on either side of the => may be empty.
If a value is written as A, B, or N, then the bytecode treats it as
an integer. If a value is written is ADDR, then the bytecode treats it
as an address.
We do not fully describe the floating point operations here; although
this design can be extended in a clean way to handle floating point
values, they are not of immediate interest to the customer, so we avoid
describing them, to save time.
'float' (0x01): =>
Prefix for floating-point bytecodes. Not implemented yet.
'add' (0x02): A B => A+B
Pop two integers from the stack, and push their sum, as an integer.
'sub' (0x03): A B => A-B
Pop two integers from the stack, subtract the top value from the
next-to-top value, and push the difference.
'mul' (0x04): A B => A*B
Pop two integers from the stack, multiply them, and push the
product on the stack. Note that, when one multiplies two N-bit
numbers yielding another N-bit number, it is irrelevant whether the
numbers are signed or not; the results are the same.
'div_signed' (0x05): A B => A/B
Pop two signed integers from the stack; divide the next-to-top
value by the top value, and push the quotient. If the divisor is
zero, terminate with an error.
'div_unsigned' (0x06): A B => A/B
Pop two unsigned integers from the stack; divide the next-to-top
value by the top value, and push the quotient. If the divisor is
zero, terminate with an error.
'rem_signed' (0x07): A B => A MODULO B
Pop two signed integers from the stack; divide the next-to-top
value by the top value, and push the remainder. If the divisor is
zero, terminate with an error.
'rem_unsigned' (0x08): A B => A MODULO B
Pop two unsigned integers from the stack; divide the next-to-top
value by the top value, and push the remainder. If the divisor is
zero, terminate with an error.
'lsh' (0x09): A B => A<<B
Pop two integers from the stack; let A be the next-to-top value,
and B be the top value. Shift A left by B bits, and push the
result.
'rsh_signed' (0x0a): A B => '(signed)'A>>B
Pop two integers from the stack; let A be the next-to-top value,
and B be the top value. Shift A right by B bits, inserting copies
of the top bit at the high end, and push the result.
'rsh_unsigned' (0x0b): A B => A>>B
Pop two integers from the stack; let A be the next-to-top value,
and B be the top value. Shift A right by B bits, inserting zero
bits at the high end, and push the result.
'log_not' (0x0e): A => !A
Pop an integer from the stack; if it is zero, push the value one;
otherwise, push the value zero.
'bit_and' (0x0f): A B => A&B
Pop two integers from the stack, and push their bitwise 'and'.
'bit_or' (0x10): A B => A|B
Pop two integers from the stack, and push their bitwise 'or'.
'bit_xor' (0x11): A B => A^B
Pop two integers from the stack, and push their bitwise
exclusive-'or'.
'bit_not' (0x12): A => ~A
Pop an integer from the stack, and push its bitwise complement.
'equal' (0x13): A B => A=B
Pop two integers from the stack; if they are equal, push the value
one; otherwise, push the value zero.
'less_signed' (0x14): A B => A<B
Pop two signed integers from the stack; if the next-to-top value is
less than the top value, push the value one; otherwise, push the
value zero.
'less_unsigned' (0x15): A B => A<B
Pop two unsigned integers from the stack; if the next-to-top value
is less than the top value, push the value one; otherwise, push the
value zero.
'ext' (0x16) N: A => A, sign-extended from N bits
Pop an unsigned value from the stack; treating it as an N-bit
twos-complement value, extend it to full length. This means that
all bits to the left of bit N-1 (where the least significant bit is
bit 0) are set to the value of bit N-1. Note that N may be larger
than or equal to the width of the stack elements of the bytecode
engine; in this case, the bytecode should have no effect.
The number of source bits to preserve, N, is encoded as a single
byte unsigned integer following the 'ext' bytecode.
'zero_ext' (0x2a) N: A => A, zero-extended from N bits
Pop an unsigned value from the stack; zero all but the bottom N
bits.
The number of source bits to preserve, N, is encoded as a single
byte unsigned integer following the 'zero_ext' bytecode.
'ref8' (0x17): ADDR => A
'ref16' (0x18): ADDR => A
'ref32' (0x19): ADDR => A
'ref64' (0x1a): ADDR => A
Pop an address ADDR from the stack. For bytecode 'ref'N, fetch an
N-bit value from ADDR, using the natural target endianness. Push
the fetched value as an unsigned integer.
Note that ADDR may not be aligned in any particular way; the 'refN'
bytecodes should operate correctly for any address.
If attempting to access memory at ADDR would cause a processor
exception of some sort, terminate with an error.
'ref_float' (0x1b): ADDR => D
'ref_double' (0x1c): ADDR => D
'ref_long_double' (0x1d): ADDR => D
'l_to_d' (0x1e): A => D
'd_to_l' (0x1f): D => A
Not implemented yet.
'dup' (0x28): A => A A
Push another copy of the stack's top element.
'swap' (0x2b): A B => B A
Exchange the top two items on the stack.
'pop' (0x29): A =>
Discard the top value on the stack.
'pick' (0x32) N: A ... B => A ... B A
Duplicate an item from the stack and push it on the top of the
stack. N, a single byte, indicates the stack item to copy. If N
is zero, this is the same as 'dup'; if N is one, it copies the item
under the top item, etc. If N exceeds the number of items on the
stack, terminate with an error.
'rot' (0x33): A B C => C A B
Rotate the top three items on the stack. The top item (c) becomes
the third item, the next-to-top item (b) becomes the top item and
the third item (a) from the top becomes the next-to-top item.
'if_goto' (0x20) OFFSET: A =>
Pop an integer off the stack; if it is non-zero, branch to the
given offset in the bytecode string. Otherwise, continue to the
next instruction in the bytecode stream. In other words, if A is
non-zero, set the 'pc' register to 'start' + OFFSET. Thus, an
offset of zero denotes the beginning of the expression.
The OFFSET is stored as a sixteen-bit unsigned value, stored
immediately following the 'if_goto' bytecode. It is always stored
most significant byte first, regardless of the target's normal
endianness. The offset is not guaranteed to fall at any particular
alignment within the bytecode stream; thus, on machines where
fetching a 16-bit on an unaligned address raises an exception, you
should fetch the offset one byte at a time.
'goto' (0x21) OFFSET: =>
Branch unconditionally to OFFSET; in other words, set the 'pc'
register to 'start' + OFFSET.
The offset is stored in the same way as for the 'if_goto' bytecode.
'const8' (0x22) N: => N
'const16' (0x23) N: => N
'const32' (0x24) N: => N
'const64' (0x25) N: => N
Push the integer constant N on the stack, without sign extension.
To produce a small negative value, push a small twos-complement
value, and then sign-extend it using the 'ext' bytecode.
The constant N is stored in the appropriate number of bytes
following the 'const'B bytecode. The constant N is always stored
most significant byte first, regardless of the target's normal
endianness. The constant is not guaranteed to fall at any
particular alignment within the bytecode stream; thus, on machines
where fetching a 16-bit on an unaligned address raises an
exception, you should fetch N one byte at a time.
'reg' (0x26) N: => A
Push the value of register number N, without sign extension. The
registers are numbered following GDB's conventions.
The register number N is encoded as a 16-bit unsigned integer
immediately following the 'reg' bytecode. It is always stored most
significant byte first, regardless of the target's normal
endianness. The register number is not guaranteed to fall at any
particular alignment within the bytecode stream; thus, on machines
where fetching a 16-bit on an unaligned address raises an
exception, you should fetch the register number one byte at a time.
'getv' (0x2c) N: => V
Push the value of trace state variable number N, without sign
extension.
The variable number N is encoded as a 16-bit unsigned integer
immediately following the 'getv' bytecode. It is always stored
most significant byte first, regardless of the target's normal
endianness. The variable number is not guaranteed to fall at any
particular alignment within the bytecode stream; thus, on machines
where fetching a 16-bit on an unaligned address raises an
exception, you should fetch the register number one byte at a time.
'setv' (0x2d) N: V => V
Set trace state variable number N to the value found on the top of
the stack. The stack is unchanged, so that the value is readily
available if the assignment is part of a larger expression. The
handling of N is as described for 'getv'.
'trace' (0x0c): ADDR SIZE =>
Record the contents of the SIZE bytes at ADDR in a trace buffer,
for later retrieval by GDB.
'trace_quick' (0x0d) SIZE: ADDR => ADDR
Record the contents of the SIZE bytes at ADDR in a trace buffer,
for later retrieval by GDB. SIZE is a single byte unsigned integer
following the 'trace' opcode.
This bytecode is equivalent to the sequence 'dup const8 SIZE
trace', but we provide it anyway to save space in bytecode strings.
'trace16' (0x30) SIZE: ADDR => ADDR
Identical to trace_quick, except that SIZE is a 16-bit big-endian
unsigned integer, not a single byte. This should probably have
been named 'trace_quick16', for consistency.
'tracev' (0x2e) N: => A
Record the value of trace state variable number N in the trace
buffer. The handling of N is as described for 'getv'.
'tracenz' (0x2f) ADDR SIZE =>
Record the bytes at ADDR in a trace buffer, for later retrieval by
GDB. Stop at either the first zero byte, or when SIZE bytes have
been recorded, whichever occurs first.
'printf' (0x34) NUMARGS STRING =>
Do a formatted print, in the style of the C function 'printf').
The value of NUMARGS is the number of arguments to expect on the
stack, while STRING is the format string, prefixed with a two-byte
length. The last byte of the string must be zero, and is included
in the length. The format string includes escaped sequences just
as it appears in C source, so for instance the format string
'"\t%d\n"' is six characters long, and the output will consist of a
tab character, a decimal number, and a newline. At the top of the
stack, above the values to be printed, this bytecode will pop a
"function" and "channel". If the function is nonzero, then the
target may treat it as a function and call it, passing the channel
as a first argument, as with the C function 'fprintf'. If the
function is zero, then the target may simply call a standard
formatted print function of its choice. In all, this bytecode pops
2 + NUMARGS stack elements, and pushes nothing.
'end' (0x27): =>
Stop executing bytecode; the result should be the top element of
the stack. If the purpose of the expression was to compute an
lvalue or a range of memory, then the next-to-top of the stack is
the lvalue's address, and the top of the stack is the lvalue's
size, in bytes.

File: gdb.info, Node: Using Agent Expressions, Next: Varying Target Capabilities, Prev: Bytecode Descriptions, Up: Agent Expressions
F.3 Using Agent Expressions
===========================
Agent expressions can be used in several different ways by GDB, and the
debugger can generate different bytecode sequences as appropriate.
One possibility is to do expression evaluation on the target rather
than the host, such as for the conditional of a conditional tracepoint.
In such a case, GDB compiles the source expression into a bytecode
sequence that simply gets values from registers or memory, does
arithmetic, and returns a result.
Another way to use agent expressions is for tracepoint data
collection. GDB generates a different bytecode sequence for collection;
in addition to bytecodes that do the calculation, GDB adds 'trace'
bytecodes to save the pieces of memory that were used.
* The user selects trace points in the program's code at which GDB
should collect data.
* The user specifies expressions to evaluate at each trace point.
These expressions may denote objects in memory, in which case those
objects' contents are recorded as the program runs, or computed
values, in which case the values themselves are recorded.
* GDB transmits the tracepoints and their associated expressions to
the GDB agent, running on the debugging target.
* The agent arranges to be notified when a trace point is hit.
* When execution on the target reaches a trace point, the agent
evaluates the expressions associated with that trace point, and
records the resulting values and memory ranges.
* Later, when the user selects a given trace event and inspects the
objects and expression values recorded, GDB talks to the agent to
retrieve recorded data as necessary to meet the user's requests.
If the user asks to see an object whose contents have not been
recorded, GDB reports an error.

File: gdb.info, Node: Varying Target Capabilities, Next: Rationale, Prev: Using Agent Expressions, Up: Agent Expressions
F.4 Varying Target Capabilities
===============================
Some targets don't support floating-point, and some would rather not
have to deal with 'long long' operations. Also, different targets will
have different stack sizes, and different bytecode buffer lengths.
Thus, GDB needs a way to ask the target about itself. We haven't
worked out the details yet, but in general, GDB should be able to send
the target a packet asking it to describe itself. The reply should be a
packet whose length is explicit, so we can add new information to the
packet in future revisions of the agent, without confusing old versions
of GDB, and it should contain a version number. It should contain at
least the following information:
* whether floating point is supported
* whether 'long long' is supported
* maximum acceptable size of bytecode stack
* maximum acceptable length of bytecode expressions
* which registers are actually available for collection
* whether the target supports disabled tracepoints

File: gdb.info, Node: Rationale, Prev: Varying Target Capabilities, Up: Agent Expressions
F.5 Rationale
=============
Some of the design decisions apparent above are arguable.
What about stack overflow/underflow?
GDB should be able to query the target to discover its stack size.
Given that information, GDB can determine at translation time
whether a given expression will overflow the stack. But this spec
isn't about what kinds of error-checking GDB ought to do.
Why are you doing everything in LONGEST?
Speed isn't important, but agent code size is; using LONGEST brings
in a bunch of support code to do things like division, etc. So
this is a serious concern.
First, note that you don't need different bytecodes for different
operand sizes. You can generate code without _knowing_ how big the
stack elements actually are on the target. If the target only
supports 32-bit ints, and you don't send any 64-bit bytecodes,
everything just works. The observation here is that the MIPS and
the Alpha have only fixed-size registers, and you can still get C's
semantics even though most instructions only operate on full-sized
words. You just need to make sure everything is properly
sign-extended at the right times. So there is no need for 32- and
64-bit variants of the bytecodes. Just implement everything using
the largest size you support.
GDB should certainly check to see what sizes the target supports,
so the user can get an error earlier, rather than later. But this
information is not necessary for correctness.
Why don't you have '>' or '<=' operators?
I want to keep the interpreter small, and we don't need them. We
can combine the 'less_' opcodes with 'log_not', and swap the order
of the operands, yielding all four asymmetrical comparison
operators. For example, '(x <= y)' is '! (x > y)', which is '! (y
< x)'.
Why do you have 'log_not'?
Why do you have 'ext'?
Why do you have 'zero_ext'?
These are all easily synthesized from other instructions, but I
expect them to be used frequently, and they're simple, so I include
them to keep bytecode strings short.
'log_not' is equivalent to 'const8 0 equal'; it's used in half the
relational operators.
'ext N' is equivalent to 'const8 S-N lsh const8 S-N rsh_signed',
where S is the size of the stack elements; it follows 'refM' and
REG bytecodes when the value should be signed. See the next
bulleted item.
'zero_ext N' is equivalent to 'constM MASK log_and'; it's used
whenever we push the value of a register, because we can't assume
the upper bits of the register aren't garbage.
Why not have sign-extending variants of the 'ref' operators?
Because that would double the number of 'ref' operators, and we
need the 'ext' bytecode anyway for accessing bitfields.
Why not have constant-address variants of the 'ref' operators?
Because that would double the number of 'ref' operators again, and
'const32 ADDRESS ref32' is only one byte longer.
Why do the 'refN' operators have to support unaligned fetches?
GDB will generate bytecode that fetches multi-byte values at
unaligned addresses whenever the executable's debugging information
tells it to. Furthermore, GDB does not know the value the pointer
will have when GDB generates the bytecode, so it cannot determine
whether a particular fetch will be aligned or not.
In particular, structure bitfields may be several bytes long, but
follow no alignment rules; members of packed structures are not
necessarily aligned either.
In general, there are many cases where unaligned references occur
in correct C code, either at the programmer's explicit request, or
at the compiler's discretion. Thus, it is simpler to make the GDB
agent bytecodes work correctly in all circumstances than to make
GDB guess in each case whether the compiler did the usual thing.
Why are there no side-effecting operators?
Because our current client doesn't want them? That's a cheap
answer. I think the real answer is that I'm afraid of implementing
function calls. We should re-visit this issue after the present
contract is delivered.
Why aren't the 'goto' ops PC-relative?
The interpreter has the base address around anyway for PC bounds
checking, and it seemed simpler.
Why is there only one offset size for the 'goto' ops?
Offsets are currently sixteen bits. I'm not happy with this
situation either:
Suppose we have multiple branch ops with different offset sizes.
As I generate code left-to-right, all my jumps are forward jumps
(there are no loops in expressions), so I never know the target
when I emit the jump opcode. Thus, I have to either always assume
the largest offset size, or do jump relaxation on the code after I
generate it, which seems like a big waste of time.
I can imagine a reasonable expression being longer than 256 bytes.
I can't imagine one being longer than 64k. Thus, we need 16-bit
offsets. This kind of reasoning is so bogus, but relaxation is
pathetic.
The other approach would be to generate code right-to-left. Then
I'd always know my offset size. That might be fun.
Where is the function call bytecode?
When we add side-effects, we should add this.
Why does the 'reg' bytecode take a 16-bit register number?
Intel's IA-64 architecture has 128 general-purpose registers, and
128 floating-point registers, and I'm sure it has some random
control registers.
Why do we need 'trace' and 'trace_quick'?
Because GDB needs to record all the memory contents and registers
an expression touches. If the user wants to evaluate an expression
'x->y->z', the agent must record the values of 'x' and 'x->y' as
well as the value of 'x->y->z'.
Don't the 'trace' bytecodes make the interpreter less general?
They do mean that the interpreter contains special-purpose code,
but that doesn't mean the interpreter can only be used for that
purpose. If an expression doesn't use the 'trace' bytecodes, they
don't get in its way.
Why doesn't 'trace_quick' consume its arguments the way everything else does?
In general, you do want your operators to consume their arguments;
it's consistent, and generally reduces the amount of stack
rearrangement necessary. However, 'trace_quick' is a kludge to
save space; it only exists so we needn't write 'dup const8 SIZE
trace' before every memory reference. Therefore, it's okay for it
not to consume its arguments; it's meant for a specific context in
which we know exactly what it should do with the stack. If we're
going to have a kludge, it should be an effective kludge.
Why does 'trace16' exist?
That opcode was added by the customer that contracted Cygnus for
the data tracing work. I personally think it is unnecessary;
objects that large will be quite rare, so it is okay to use 'dup
const16 SIZE trace' in those cases.
Whatever we decide to do with 'trace16', we should at least leave
opcode 0x30 reserved, to remain compatible with the customer who
added it.

File: gdb.info, Node: Target Descriptions, Next: Operating System Information, Prev: Agent Expressions, Up: Top
Appendix G Target Descriptions
******************************
One of the challenges of using GDB to debug embedded systems is that
there are so many minor variants of each processor architecture in use.
It is common practice for vendors to start with a standard processor
core -- ARM, PowerPC, or MIPS, for example -- and then make changes to
adapt it to a particular market niche. Some architectures have hundreds
of variants, available from dozens of vendors. This leads to a number
of problems:
* With so many different customized processors, it is difficult for
the GDB maintainers to keep up with the changes.
* Since individual variants may have short lifetimes or limited
audiences, it may not be worthwhile to carry information about
every variant in the GDB source tree.
* When GDB does support the architecture of the embedded system at
hand, the task of finding the correct architecture name to give the
'set architecture' command can be error-prone.
To address these problems, the GDB remote protocol allows a target
system to not only identify itself to GDB, but to actually describe its
own features. This lets GDB support processor variants it has never
seen before -- to the extent that the descriptions are accurate, and
that GDB understands them.
GDB must be linked with the Expat library to support XML target
descriptions. *Note Expat::.
* Menu:
* Retrieving Descriptions:: How descriptions are fetched from a target.
* Target Description Format:: The contents of a target description.
* Predefined Target Types:: Standard types available for target
descriptions.
* Enum Target Types:: How to define enum target types.
* Standard Target Features:: Features GDB knows about.

File: gdb.info, Node: Retrieving Descriptions, Next: Target Description Format, Up: Target Descriptions
G.1 Retrieving Descriptions
===========================
Target descriptions can be read from the target automatically, or
specified by the user manually. The default behavior is to read the
description from the target. GDB retrieves it via the remote protocol
using 'qXfer' requests (*note qXfer: General Query Packets.). The ANNEX
in the 'qXfer' packet will be 'target.xml'. The contents of the
'target.xml' annex are an XML document, of the form described in *note
Target Description Format::.
Alternatively, you can specify a file to read for the target
description. If a file is set, the target will not be queried. The
commands to specify a file are:
'set tdesc filename PATH'
Read the target description from PATH.
'unset tdesc filename'
Do not read the XML target description from a file. GDB will use
the description supplied by the current target.
'show tdesc filename'
Show the filename to read for a target description, if any.

File: gdb.info, Node: Target Description Format, Next: Predefined Target Types, Prev: Retrieving Descriptions, Up: Target Descriptions
G.2 Target Description Format
=============================
A target description annex is an XML (http://www.w3.org/XML/) document
which complies with the Document Type Definition provided in the GDB
sources in 'gdb/features/gdb-target.dtd'. This means you can use
generally available tools like 'xmllint' to check that your feature
descriptions are well-formed and valid. However, to help people
unfamiliar with XML write descriptions for their targets, we also
describe the grammar here.
Target descriptions can identify the architecture of the remote
target and (for some architectures) provide information about custom
register sets. They can also identify the OS ABI of the remote target.
GDB can use this information to autoconfigure for your target, or to
warn you if you connect to an unsupported target.
Here is a simple target description:
<target version="1.0">
<architecture>i386:x86-64</architecture>
</target>
This minimal description only says that the target uses the x86-64
architecture.
A target description has the following overall form, with [ ] marking
optional elements and ... marking repeatable elements. The elements are
explained further below.
<?xml version="1.0"?>
<!DOCTYPE target SYSTEM "gdb-target.dtd">
<target version="1.0">
[ARCHITECTURE]
[OSABI]
[COMPATIBLE]
[FEATURE...]
</target>
The description is generally insensitive to whitespace and line breaks,
under the usual common-sense rules. The XML version declaration and
document type declaration can generally be omitted (GDB does not require
them), but specifying them may be useful for XML validation tools. The
'version' attribute for '<target>' may also be omitted, but we recommend
including it; if future versions of GDB use an incompatible revision of
'gdb-target.dtd', they will detect and report the version mismatch.
G.2.1 Inclusion
---------------
It can sometimes be valuable to split a target description up into
several different annexes, either for organizational purposes, or to
share files between different possible target descriptions. You can
divide a description into multiple files by replacing any element of the
target description with an inclusion directive of the form:
<xi:include href="DOCUMENT"/>
When GDB encounters an element of this form, it will retrieve the named
XML DOCUMENT, and replace the inclusion directive with the contents of
that document. If the current description was read using 'qXfer', then
so will be the included document; DOCUMENT will be interpreted as the
name of an annex. If the current description was read from a file, GDB
will look for DOCUMENT as a file in the same directory where it found
the original description.
G.2.2 Architecture
------------------
An '<architecture>' element has this form:
<architecture>ARCH</architecture>
ARCH is one of the architectures from the set accepted by 'set
architecture' (*note Specifying a Debugging Target: Targets.).
G.2.3 OS ABI
------------
This optional field was introduced in GDB version 7.0. Previous
versions of GDB ignore it.
An '<osabi>' element has this form:
<osabi>ABI-NAME</osabi>
ABI-NAME is an OS ABI name from the same selection accepted by
'set osabi' (*note Configuring the Current ABI: ABI.).
G.2.4 Compatible Architecture
-----------------------------
This optional field was introduced in GDB version 7.0. Previous
versions of GDB ignore it.
A '<compatible>' element has this form:
<compatible>ARCH</compatible>
ARCH is one of the architectures from the set accepted by 'set
architecture' (*note Specifying a Debugging Target: Targets.).
A '<compatible>' element is used to specify that the target is able
to run binaries in some other than the main target architecture given by
the '<architecture>' element. For example, on the Cell Broadband
Engine, the main architecture is 'powerpc:common' or 'powerpc:common64',
but the system is able to run binaries in the 'spu' architecture as
well. The way to describe this capability with '<compatible>' is as
follows:
<architecture>powerpc:common</architecture>
<compatible>spu</compatible>
G.2.5 Features
--------------
Each '<feature>' describes some logical portion of the target system.
Features are currently used to describe available CPU registers and the
types of their contents. A '<feature>' element has this form:
<feature name="NAME">
[TYPE...]
REG...
</feature>
Each feature's name should be unique within the description. The name
of a feature does not matter unless GDB has some special knowledge of
the contents of that feature; if it does, the feature should have its
standard name. *Note Standard Target Features::.
G.2.6 Types
-----------
Any register's value is a collection of bits which GDB must interpret.
The default interpretation is a two's complement integer, but other
types can be requested by name in the register description. Some
predefined types are provided by GDB (*note Predefined Target Types::),
and the description can define additional composite and enum types.
Each type element must have an 'id' attribute, which gives a unique
(within the containing '<feature>') name to the type. Types must be
defined before they are used.
Some targets offer vector registers, which can be treated as arrays
of scalar elements. These types are written as '<vector>' elements,
specifying the array element type, TYPE, and the number of elements,
COUNT:
<vector id="ID" type="TYPE" count="COUNT"/>
If a register's value is usefully viewed in multiple ways, define it
with a union type containing the useful representations. The '<union>'
element contains one or more '<field>' elements, each of which has a
NAME and a TYPE:
<union id="ID">
<field name="NAME" type="TYPE"/>
...
</union>
If a register's value is composed from several separate values,
define it with either a structure type or a flags type. A flags type
may only contain bitfields. A structure type may either contain only
bitfields or contain no bitfields. If the value contains only
bitfields, its total size in bytes must be specified.
Non-bitfield values have a NAME and TYPE.
<struct id="ID">
<field name="NAME" type="TYPE"/>
...
</struct>
Both NAME and TYPE values are required. No implicit padding is
added.
Bitfield values have a NAME, START, END and TYPE.
<struct id="ID" size="SIZE">
<field name="NAME" start="START" end="END" type="TYPE"/>
...
</struct>
<flags id="ID" size="SIZE">
<field name="NAME" start="START" end="END" type="TYPE"/>
...
</flags>
The NAME value is required. Bitfield values may be named with the
empty string, '""', in which case the field is "filler" and its value is
not printed. Not all bits need to be specified, so "filler" fields are
optional.
The START and END values are required, and TYPE is optional. The
field's START must be less than or equal to its END, and zero represents
the least significant bit.
The default value of TYPE is 'bool' for single bit fields, and an
unsigned integer otherwise.
Which to choose? Structures or flags?
Registers defined with 'flags' have these advantages over defining
them with 'struct':
* Arithmetic may be performed on them as if they were integers.
* They are printed in a more readable fashion.
Registers defined with 'struct' have one advantage over defining them
with 'flags':
* One can fetch individual fields like in 'C'.
(gdb) print $my_struct_reg.field3
$1 = 42
G.2.7 Registers
---------------
Each register is represented as an element with this form:
<reg name="NAME"
bitsize="SIZE"
[regnum="NUM"]
[save-restore="SAVE-RESTORE"]
[type="TYPE"]
[group="GROUP"]/>
The components are as follows:
NAME
The register's name; it must be unique within the target
description.
BITSIZE
The register's size, in bits.
REGNUM
The register's number. If omitted, a register's number is one
greater than that of the previous register (either in the current
feature or in a preceding feature); the first register in the
target description defaults to zero. This register number is used
to read or write the register; e.g. it is used in the remote 'p'
and 'P' packets, and registers appear in the 'g' and 'G' packets in
order of increasing register number.
SAVE-RESTORE
Whether the register should be preserved across inferior function
calls; this must be either 'yes' or 'no'. The default is 'yes',
which is appropriate for most registers except for some system
control registers; this is not related to the target's ABI.
TYPE
The type of the register. It may be a predefined type, a type
defined in the current feature, or one of the special types 'int'
and 'float'. 'int' is an integer type of the correct size for
BITSIZE, and 'float' is a floating point type (in the
architecture's normal floating point format) of the correct size
for BITSIZE. The default is 'int'.
GROUP
The register group to which this register belongs. It can be one
of the standard register groups 'general', 'float', 'vector' or an
arbitrary string. Group names should be limited to alphanumeric
characters. If a group name is made up of multiple words the words
may be separated by hyphens; e.g. 'special-group' or
'ultra-special-group'. If no GROUP is specified, GDB will not
display the register in 'info registers'.

File: gdb.info, Node: Predefined Target Types, Next: Enum Target Types, Prev: Target Description Format, Up: Target Descriptions
G.3 Predefined Target Types
===========================
Type definitions in the self-description can build up composite types
from basic building blocks, but can not define fundamental types.
Instead, standard identifiers are provided by GDB for the fundamental
types. The currently supported types are:
'bool'
Boolean type, occupying a single bit.
'int8'
'int16'
'int24'
'int32'
'int64'
'int128'
Signed integer types holding the specified number of bits.
'uint8'
'uint16'
'uint24'
'uint32'
'uint64'
'uint128'
Unsigned integer types holding the specified number of bits.
'code_ptr'
'data_ptr'
Pointers to unspecified code and data. The program counter and any
dedicated return address register may be marked as code pointers;
printing a code pointer converts it into a symbolic address. The
stack pointer and any dedicated address registers may be marked as
data pointers.
'ieee_single'
Single precision IEEE floating point.
'ieee_double'
Double precision IEEE floating point.
'arm_fpa_ext'
The 12-byte extended precision format used by ARM FPA registers.
'i387_ext'
The 10-byte extended precision format used by x87 registers.
'i386_eflags'
32bit EFLAGS register used by x86.
'i386_mxcsr'
32bit MXCSR register used by x86.

File: gdb.info, Node: Enum Target Types, Next: Standard Target Features, Prev: Predefined Target Types, Up: Target Descriptions
G.4 Enum Target Types
=====================
Enum target types are useful in 'struct' and 'flags' register
descriptions. *Note Target Description Format::.
Enum types have a name, size and a list of name/value pairs.
<enum id="ID" size="SIZE">
<evalue name="NAME" value="VALUE"/>
...
</enum>
Enums must be defined before they are used.
<enum id="levels_type" size="4">
<evalue name="low" value="0"/>
<evalue name="high" value="1"/>
</enum>
<flags id="flags_type" size="4">
<field name="X" start="0"/>
<field name="LEVEL" start="1" end="1" type="levels_type"/>
</flags>
<reg name="flags" bitsize="32" type="flags_type"/>
Given that description, a value of 3 for the 'flags' register would
be printed as:
(gdb) info register flags
flags 0x3 [ X LEVEL=high ]

File: gdb.info, Node: Standard Target Features, Prev: Enum Target Types, Up: Target Descriptions
G.5 Standard Target Features
============================
A target description must contain either no registers or all the
target's registers. If the description contains no registers, then GDB
will assume a default register layout, selected based on the
architecture. If the description contains any registers, the default
layout will not be used; the standard registers must be described in the
target description, in such a way that GDB can recognize them.
This is accomplished by giving specific names to feature elements
which contain standard registers. GDB will look for features with those
names and verify that they contain the expected registers; if any known
feature is missing required registers, or if any required feature is
missing, GDB will reject the target description. You can add additional
registers to any of the standard features -- GDB will display them just
as if they were added to an unrecognized feature.
This section lists the known features and their expected contents.
Sample XML documents for these features are included in the GDB source
tree, in the directory 'gdb/features'.
Names recognized by GDB should include the name of the company or
organization which selected the name, and the overall architecture to
which the feature applies; so e.g. the feature containing ARM core
registers is named 'org.gnu.gdb.arm.core'.
The names of registers are not case sensitive for the purpose of
recognizing standard features, but GDB will only display registers using
the capitalization used in the description.
* Menu:
* AArch64 Features::
* ARC Features::
* ARM Features::
* i386 Features::
* MicroBlaze Features::
* MIPS Features::
* M68K Features::
* NDS32 Features::
* Nios II Features::
* OpenRISC 1000 Features::
* PowerPC Features::
* RISC-V Features::
* RX Features::
* S/390 and System z Features::
* Sparc Features::
* TIC6x Features::

File: gdb.info, Node: AArch64 Features, Next: ARC Features, Up: Standard Target Features
G.5.1 AArch64 Features
----------------------
The 'org.gnu.gdb.aarch64.core' feature is required for AArch64 targets.
It should contain registers 'x0' through 'x30', 'sp', 'pc', and 'cpsr'.
The 'org.gnu.gdb.aarch64.fpu' feature is optional. If present, it
should contain registers 'v0' through 'v31', 'fpsr', and 'fpcr'.
The 'org.gnu.gdb.aarch64.sve' feature is optional. If present, it
should contain registers 'z0' through 'z31', 'p0' through 'p15', 'ffr'
and 'vg'.
The 'org.gnu.gdb.aarch64.pauth' feature is optional. If present, it
should contain registers 'pauth_dmask' and 'pauth_cmask'.

File: gdb.info, Node: ARC Features, Next: ARM Features, Prev: AArch64 Features, Up: Standard Target Features
G.5.2 ARC Features
------------------
ARC processors are highly configurable, so even core registers and their
number are not completely predetermined. In addition flags and PC
registers which are important to GDB are not "core" registers in ARC. It
is required that one of the core registers features is present.
'org.gnu.gdb.arc.aux-minimal' feature is mandatory.
The 'org.gnu.gdb.arc.core.v2' feature is required for ARC EM and ARC
HS targets with a normal register file. It should contain registers
'r0' through 'r25', 'gp', 'fp', 'sp', 'r30', 'blink', 'lp_count' and
'pcl'. This feature may contain register 'ilink' and any of extension
core registers 'r32' through 'r59/acch'. 'ilink' and extension core
registers are not available to read/write, when debugging GNU/Linux
applications, thus 'ilink' is made optional.
The 'org.gnu.gdb.arc.core-reduced.v2' feature is required for ARC EM
and ARC HS targets with a reduced register file. It should contain
registers 'r0' through 'r3', 'r10' through 'r15', 'gp', 'fp', 'sp',
'r30', 'blink', 'lp_count' and 'pcl'. This feature may contain register
'ilink' and any of extension core registers 'r32' through 'r59/acch'.
The 'org.gnu.gdb.arc.core.arcompact' feature is required for
ARCompact targets with a normal register file. It should contain
registers 'r0' through 'r25', 'gp', 'fp', 'sp', 'r30', 'blink',
'lp_count' and 'pcl'. This feature may contain registers 'ilink1',
'ilink2' and any of extension core registers 'r32' through 'r59/acch'.
'ilink1' and 'ilink2' and extension core registers are not available
when debugging GNU/Linux applications. The only difference with
'org.gnu.gdb.arc.core.v2' feature is in the names of 'ilink1' and
'ilink2' registers and that 'r30' is mandatory in ARC v2, but 'ilink2'
is optional on ARCompact.
The 'org.gnu.gdb.arc.aux-minimal' feature is required for all ARC
targets. It should contain registers 'pc' and 'status32'.

File: gdb.info, Node: ARM Features, Next: i386 Features, Prev: ARC Features, Up: Standard Target Features
G.5.3 ARM Features
------------------
The 'org.gnu.gdb.arm.core' feature is required for non-M-profile ARM
targets. It should contain registers 'r0' through 'r13', 'sp', 'lr',
'pc', and 'cpsr'.
For M-profile targets (e.g. Cortex-M3), the 'org.gnu.gdb.arm.core'
feature is replaced by 'org.gnu.gdb.arm.m-profile'. It should contain
registers 'r0' through 'r13', 'sp', 'lr', 'pc', and 'xpsr'.
The 'org.gnu.gdb.arm.fpa' feature is optional. If present, it should
contain registers 'f0' through 'f7' and 'fps'.
The 'org.gnu.gdb.xscale.iwmmxt' feature is optional. If present, it
should contain at least registers 'wR0' through 'wR15' and 'wCGR0'
through 'wCGR3'. The 'wCID', 'wCon', 'wCSSF', and 'wCASF' registers are
optional.
The 'org.gnu.gdb.arm.vfp' feature is optional. If present, it should
contain at least registers 'd0' through 'd15'. If they are present,
'd16' through 'd31' should also be included. GDB will synthesize the
single-precision registers from halves of the double-precision
registers.
The 'org.gnu.gdb.arm.neon' feature is optional. It does not need to
contain registers; it instructs GDB to display the VFP double-precision
registers as vectors and to synthesize the quad-precision registers from
pairs of double-precision registers. If this feature is present,
'org.gnu.gdb.arm.vfp' must also be present and include 32
double-precision registers.

File: gdb.info, Node: i386 Features, Next: MicroBlaze Features, Prev: ARM Features, Up: Standard Target Features
G.5.4 i386 Features
-------------------
The 'org.gnu.gdb.i386.core' feature is required for i386/amd64 targets.
It should describe the following registers:
- 'eax' through 'edi' plus 'eip' for i386
- 'rax' through 'r15' plus 'rip' for amd64
- 'eflags', 'cs', 'ss', 'ds', 'es', 'fs', 'gs'
- 'st0' through 'st7'
- 'fctrl', 'fstat', 'ftag', 'fiseg', 'fioff', 'foseg', 'fooff' and
'fop'
The register sets may be different, depending on the target.
The 'org.gnu.gdb.i386.sse' feature is optional. It should describe
registers:
- 'xmm0' through 'xmm7' for i386
- 'xmm0' through 'xmm15' for amd64
- 'mxcsr'
The 'org.gnu.gdb.i386.avx' feature is optional and requires the
'org.gnu.gdb.i386.sse' feature. It should describe the upper 128 bits
of YMM registers:
- 'ymm0h' through 'ymm7h' for i386
- 'ymm0h' through 'ymm15h' for amd64
The 'org.gnu.gdb.i386.mpx' is an optional feature representing Intel
Memory Protection Extension (MPX). It should describe the following
registers:
- 'bnd0raw' through 'bnd3raw' for i386 and amd64.
- 'bndcfgu' and 'bndstatus' for i386 and amd64.
The 'org.gnu.gdb.i386.linux' feature is optional. It should describe
a single register, 'orig_eax'.
The 'org.gnu.gdb.i386.segments' feature is optional. It should
describe two system registers: 'fs_base' and 'gs_base'.
The 'org.gnu.gdb.i386.avx512' feature is optional and requires the
'org.gnu.gdb.i386.avx' feature. It should describe additional XMM
registers:
- 'xmm16h' through 'xmm31h', only valid for amd64.
It should describe the upper 128 bits of additional YMM registers:
- 'ymm16h' through 'ymm31h', only valid for amd64.
It should describe the upper 256 bits of ZMM registers:
- 'zmm0h' through 'zmm7h' for i386.
- 'zmm0h' through 'zmm15h' for amd64.
It should describe the additional ZMM registers:
- 'zmm16h' through 'zmm31h', only valid for amd64.
The 'org.gnu.gdb.i386.pkeys' feature is optional. It should describe
a single register, 'pkru'. It is a 32-bit register valid for i386 and
amd64.

File: gdb.info, Node: MicroBlaze Features, Next: MIPS Features, Prev: i386 Features, Up: Standard Target Features
G.5.5 MicroBlaze Features
-------------------------
The 'org.gnu.gdb.microblaze.core' feature is required for MicroBlaze
targets. It should contain registers 'r0' through 'r31', 'rpc', 'rmsr',
'rear', 'resr', 'rfsr', 'rbtr', 'rpvr', 'rpvr1' through 'rpvr11',
'redr', 'rpid', 'rzpr', 'rtlbx', 'rtlbsx', 'rtlblo', and 'rtlbhi'.
The 'org.gnu.gdb.microblaze.stack-protect' feature is optional. If
present, it should contain registers 'rshr' and 'rslr'

File: gdb.info, Node: MIPS Features, Next: M68K Features, Prev: MicroBlaze Features, Up: Standard Target Features
G.5.6 MIPS Features
-------------------
The 'org.gnu.gdb.mips.cpu' feature is required for MIPS targets. It
should contain registers 'r0' through 'r31', 'lo', 'hi', and 'pc'. They
may be 32-bit or 64-bit depending on the target.
The 'org.gnu.gdb.mips.cp0' feature is also required. It should
contain at least the 'status', 'badvaddr', and 'cause' registers. They
may be 32-bit or 64-bit depending on the target.
The 'org.gnu.gdb.mips.fpu' feature is currently required, though it
may be optional in a future version of GDB. It should contain registers
'f0' through 'f31', 'fcsr', and 'fir'. They may be 32-bit or 64-bit
depending on the target.
The 'org.gnu.gdb.mips.dsp' feature is optional. It should contain
registers 'hi1' through 'hi3', 'lo1' through 'lo3', and 'dspctl'. The
'dspctl' register should be 32-bit and the rest may be 32-bit or 64-bit
depending on the target.
The 'org.gnu.gdb.mips.linux' feature is optional. It should contain
a single register, 'restart', which is used by the Linux kernel to
control restartable syscalls.

File: gdb.info, Node: M68K Features, Next: NDS32 Features, Prev: MIPS Features, Up: Standard Target Features
G.5.7 M68K Features
-------------------
''org.gnu.gdb.m68k.core''
''org.gnu.gdb.coldfire.core''
''org.gnu.gdb.fido.core''
One of those features must be always present. The feature that is
present determines which flavor of m68k is used. The feature that
is present should contain registers 'd0' through 'd7', 'a0' through
'a5', 'fp', 'sp', 'ps' and 'pc'.
''org.gnu.gdb.coldfire.fp''
This feature is optional. If present, it should contain registers
'fp0' through 'fp7', 'fpcontrol', 'fpstatus' and 'fpiaddr'.

File: gdb.info, Node: NDS32 Features, Next: Nios II Features, Prev: M68K Features, Up: Standard Target Features
G.5.8 NDS32 Features
--------------------
The 'org.gnu.gdb.nds32.core' feature is required for NDS32 targets. It
should contain at least registers 'r0' through 'r10', 'r15', 'fp', 'gp',
'lp', 'sp', and 'pc'.
The 'org.gnu.gdb.nds32.fpu' feature is optional. If present, it
should contain 64-bit double-precision floating-point registers 'fd0'
through _fdN_, which should be 'fd3', 'fd7', 'fd15', or 'fd31' based on
the FPU configuration implemented.
_Note:_ The first sixteen 64-bit double-precision floating-point
registers are overlapped with the thirty-two 32-bit single-precision
floating-point registers. The 32-bit single-precision registers, if not
being listed explicitly, will be synthesized from halves of the
overlapping 64-bit double-precision registers. Listing 32-bit
single-precision registers explicitly is deprecated, and the support to
it could be totally removed some day.

File: gdb.info, Node: Nios II Features, Next: OpenRISC 1000 Features, Prev: NDS32 Features, Up: Standard Target Features
G.5.9 Nios II Features
----------------------
The 'org.gnu.gdb.nios2.cpu' feature is required for Nios II targets. It
should contain the 32 core registers ('zero', 'at', 'r2' through 'r23',
'et' through 'ra'), 'pc', and the 16 control registers ('status' through
'mpuacc').

File: gdb.info, Node: OpenRISC 1000 Features, Next: PowerPC Features, Prev: Nios II Features, Up: Standard Target Features
G.5.10 Openrisc 1000 Features
-----------------------------
The 'org.gnu.gdb.or1k.group0' feature is required for OpenRISC 1000
targets. It should contain the 32 general purpose registers ('r0'
through 'r31'), 'ppc', 'npc' and 'sr'.

File: gdb.info, Node: PowerPC Features, Next: RISC-V Features, Prev: OpenRISC 1000 Features, Up: Standard Target Features
G.5.11 PowerPC Features
-----------------------
The 'org.gnu.gdb.power.core' feature is required for PowerPC targets.
It should contain registers 'r0' through 'r31', 'pc', 'msr', 'cr', 'lr',
'ctr', and 'xer'. They may be 32-bit or 64-bit depending on the target.
The 'org.gnu.gdb.power.fpu' feature is optional. It should contain
registers 'f0' through 'f31' and 'fpscr'.
The 'org.gnu.gdb.power.altivec' feature is optional. It should
contain registers 'vr0' through 'vr31', 'vscr', and 'vrsave'. GDB will
define pseudo-registers 'v0' through 'v31' as aliases for the
corresponding 'vrX' registers.
The 'org.gnu.gdb.power.vsx' feature is optional. It should contain
registers 'vs0h' through 'vs31h'. GDB will combine these registers with
the floating point registers ('f0' through 'f31') and the altivec
registers ('vr0' through 'vr31') to present the 128-bit wide registers
'vs0' through 'vs63', the set of vector-scalar registers for POWER7.
Therefore, this feature requires both 'org.gnu.gdb.power.fpu' and
'org.gnu.gdb.power.altivec'.
The 'org.gnu.gdb.power.spe' feature is optional. It should contain
registers 'ev0h' through 'ev31h', 'acc', and 'spefscr'. SPE targets
should provide 32-bit registers in 'org.gnu.gdb.power.core' and provide
the upper halves in 'ev0h' through 'ev31h'. GDB will combine these to
present registers 'ev0' through 'ev31' to the user.
The 'org.gnu.gdb.power.ppr' feature is optional. It should contain
the 64-bit register 'ppr'.
The 'org.gnu.gdb.power.dscr' feature is optional. It should contain
the 64-bit register 'dscr'.
The 'org.gnu.gdb.power.tar' feature is optional. It should contain
the 64-bit register 'tar'.
The 'org.gnu.gdb.power.ebb' feature is optional. It should contain
registers 'bescr', 'ebbhr' and 'ebbrr', all 64-bit wide.
The 'org.gnu.gdb.power.linux.pmu' feature is optional. It should
contain registers 'mmcr0', 'mmcr2', 'siar', 'sdar' and 'sier', all
64-bit wide. This is the subset of the isa 2.07 server PMU registers
provided by GNU/Linux.
The 'org.gnu.gdb.power.htm.spr' feature is optional. It should
contain registers 'tfhar', 'texasr' and 'tfiar', all 64-bit wide.
The 'org.gnu.gdb.power.htm.core' feature is optional. It should
contain the checkpointed general-purpose registers 'cr0' through 'cr31',
as well as the checkpointed registers 'clr' and 'cctr'. These registers
may all be either 32-bit or 64-bit depending on the target. It should
also contain the checkpointed registers 'ccr' and 'cxer', which should
both be 32-bit wide.
The 'org.gnu.gdb.power.htm.fpu' feature is optional. It should
contain the checkpointed 64-bit floating-point registers 'cf0' through
'cf31', as well as the checkpointed 64-bit register 'cfpscr'.
The 'org.gnu.gdb.power.htm.altivec' feature is optional. It should
contain the checkpointed altivec registers 'cvr0' through 'cvr31', all
128-bit wide. It should also contain the checkpointed registers 'cvscr'
and 'cvrsave', both 32-bit wide.
The 'org.gnu.gdb.power.htm.vsx' feature is optional. It should
contain registers 'cvs0h' through 'cvs31h'. GDB will combine these
registers with the checkpointed floating point registers ('cf0' through
'cf31') and the checkpointed altivec registers ('cvr0' through 'cvr31')
to present the 128-bit wide checkpointed vector-scalar registers 'cvs0'
through 'cvs63'. Therefore, this feature requires both
'org.gnu.gdb.power.htm.altivec' and 'org.gnu.gdb.power.htm.fpu'.
The 'org.gnu.gdb.power.htm.ppr' feature is optional. It should
contain the 64-bit checkpointed register 'cppr'.
The 'org.gnu.gdb.power.htm.dscr' feature is optional. It should
contain the 64-bit checkpointed register 'cdscr'.
The 'org.gnu.gdb.power.htm.tar' feature is optional. It should
contain the 64-bit checkpointed register 'ctar'.

File: gdb.info, Node: RISC-V Features, Next: RX Features, Prev: PowerPC Features, Up: Standard Target Features
G.5.12 RISC-V Features
----------------------
The 'org.gnu.gdb.riscv.cpu' feature is required for RISC-V targets. It
should contain the registers 'x0' through 'x31', and 'pc'. Either the
architectural names ('x0', 'x1', etc) can be used, or the ABI names
('zero', 'ra', etc).
The 'org.gnu.gdb.riscv.fpu' feature is optional. If present, it
should contain registers 'f0' through 'f31', 'fflags', 'frm', and
'fcsr'. As with the cpu feature, either the architectural register
names, or the ABI names can be used.
The 'org.gnu.gdb.riscv.virtual' feature is optional. If present, it
should contain registers that are not backed by real registers on the
target, but are instead virtual, where the register value is derived
from other target state. In many ways these are like GDBs
pseudo-registers, except implemented by the target. Currently the only
register expected in this set is the one byte 'priv' register that
contains the target's privilege level in the least significant two bits.
The 'org.gnu.gdb.riscv.csr' feature is optional. If present, it
should contain all of the target's standard CSRs. Standard CSRs are
those defined in the RISC-V specification documents. There is some
overlap between this feature and the fpu feature; the 'fflags', 'frm',
and 'fcsr' registers could be in either feature. The expectation is
that these registers will be in the fpu feature if the target has
floating point hardware, but can be moved into the csr feature if the
target has the floating point control registers, but no other floating
point hardware.

File: gdb.info, Node: RX Features, Next: S/390 and System z Features, Prev: RISC-V Features, Up: Standard Target Features
G.5.13 RX Features
------------------
The 'org.gnu.gdb.rx.core' feature is required for RX targets. It should
contain the registers 'r0' through 'r15', 'usp', 'isp', 'psw', 'pc',
'intb', 'bpsw', 'bpc', 'fintv', 'fpsw', and 'acc'.

File: gdb.info, Node: S/390 and System z Features, Next: Sparc Features, Prev: RX Features, Up: Standard Target Features
G.5.14 S/390 and System z Features
----------------------------------
The 'org.gnu.gdb.s390.core' feature is required for S/390 and System z
targets. It should contain the PSW and the 16 general registers. In
particular, System z targets should provide the 64-bit registers 'pswm',
'pswa', and 'r0' through 'r15'. S/390 targets should provide the 32-bit
versions of these registers. A System z target that runs in 31-bit
addressing mode should provide 32-bit versions of 'pswm' and 'pswa', as
well as the general register's upper halves 'r0h' through 'r15h', and
their lower halves 'r0l' through 'r15l'.
The 'org.gnu.gdb.s390.fpr' feature is required. It should contain
the 64-bit registers 'f0' through 'f15', and 'fpc'.
The 'org.gnu.gdb.s390.acr' feature is required. It should contain
the 32-bit registers 'acr0' through 'acr15'.
The 'org.gnu.gdb.s390.linux' feature is optional. It should contain
the register 'orig_r2', which is 64-bit wide on System z targets and
32-bit otherwise. In addition, the feature may contain the 'last_break'
register, whose width depends on the addressing mode, as well as the
'system_call' register, which is always 32-bit wide.
The 'org.gnu.gdb.s390.tdb' feature is optional. It should contain
the 64-bit registers 'tdb0', 'tac', 'tct', 'atia', and 'tr0' through
'tr15'.
The 'org.gnu.gdb.s390.vx' feature is optional. It should contain
64-bit wide registers 'v0l' through 'v15l', which will be combined by
GDB with the floating point registers 'f0' through 'f15' to present the
128-bit wide vector registers 'v0' through 'v15'. In addition, this
feature should contain the 128-bit wide vector registers 'v16' through
'v31'.
The 'org.gnu.gdb.s390.gs' feature is optional. It should contain the
64-bit wide guarded-storage-control registers 'gsd', 'gssm', and
'gsepla'.
The 'org.gnu.gdb.s390.gsbc' feature is optional. It should contain
the 64-bit wide guarded-storage broadcast control registers 'bc_gsd',
'bc_gssm', and 'bc_gsepla'.

File: gdb.info, Node: Sparc Features, Next: TIC6x Features, Prev: S/390 and System z Features, Up: Standard Target Features
G.5.15 Sparc Features
---------------------
The 'org.gnu.gdb.sparc.cpu' feature is required for sparc32/sparc64
targets. It should describe the following registers:
- 'g0' through 'g7'
- 'o0' through 'o7'
- 'l0' through 'l7'
- 'i0' through 'i7'
They may be 32-bit or 64-bit depending on the target.
Also the 'org.gnu.gdb.sparc.fpu' feature is required for
sparc32/sparc64 targets. It should describe the following registers:
- 'f0' through 'f31'
- 'f32' through 'f62' for sparc64
The 'org.gnu.gdb.sparc.cp0' feature is required for sparc32/sparc64
targets. It should describe the following registers:
- 'y', 'psr', 'wim', 'tbr', 'pc', 'npc', 'fsr', and 'csr' for sparc32
- 'pc', 'npc', 'state', 'fsr', 'fprs', and 'y' for sparc64

File: gdb.info, Node: TIC6x Features, Prev: Sparc Features, Up: Standard Target Features
G.5.16 TMS320C6x Features
-------------------------
The 'org.gnu.gdb.tic6x.core' feature is required for TMS320C6x targets.
It should contain registers 'A0' through 'A15', registers 'B0' through
'B15', 'CSR' and 'PC'.
The 'org.gnu.gdb.tic6x.gp' feature is optional. It should contain
registers 'A16' through 'A31' and 'B16' through 'B31'.
The 'org.gnu.gdb.tic6x.c6xp' feature is optional. It should contain
registers 'TSR', 'ILC' and 'RILC'.

File: gdb.info, Node: Operating System Information, Next: Trace File Format, Prev: Target Descriptions, Up: Top
Appendix H Operating System Information
***************************************
* Menu:
* Process list::
Users of GDB often wish to obtain information about the state of the
operating system running on the target--for example the list of
processes, or the list of open files. This section describes the
mechanism that makes it possible. This mechanism is similar to the
target features mechanism (*note Target Descriptions::), but focuses on
a different aspect of target.
Operating system information is retrieved from the target via the
remote protocol, using 'qXfer' requests (*note qXfer osdata read::).
The object name in the request should be 'osdata', and the ANNEX
identifies the data to be fetched.

File: gdb.info, Node: Process list, Up: Operating System Information
H.1 Process list
================
When requesting the process list, the ANNEX field in the 'qXfer' request
should be 'processes'. The returned data is an XML document. The
formal syntax of this document is defined in 'gdb/features/osdata.dtd'.
An example document is:
<?xml version="1.0"?>
<!DOCTYPE target SYSTEM "osdata.dtd">
<osdata type="processes">
<item>
<column name="pid">1</column>
<column name="user">root</column>
<column name="command">/sbin/init</column>
<column name="cores">1,2,3</column>
</item>
</osdata>
Each item should include a column whose name is 'pid'. The value of
that column should identify the process on the target. The 'user' and
'command' columns are optional, and will be displayed by GDB. The
'cores' column, if present, should contain a comma-separated list of
cores that this process is running on. Target may provide additional
columns, which GDB currently ignores.

File: gdb.info, Node: Trace File Format, Next: Index Section Format, Prev: Operating System Information, Up: Top
Appendix I Trace File Format
****************************
The trace file comes in three parts: a header, a textual description
section, and a trace frame section with binary data.
The header has the form '\x7fTRACE0\n'. The first byte is '0x7f' so
as to indicate that the file contains binary data, while the '0' is a
version number that may have different values in the future.
The description section consists of multiple lines of ASCII text
separated by newline characters ('0xa'). The lines may include a
variety of optional descriptive or context-setting information, such as
tracepoint definitions or register set size. GDB will ignore any line
that it does not recognize. An empty line marks the end of this
section.
'R SIZE'
Specifies the size of a register block in bytes. This is equal to
the size of a 'g' packet payload in the remote protocol. SIZE is
an ascii decimal number. There should be only one such line in a
single trace file.
'status STATUS'
Trace status. STATUS has the same format as a 'qTStatus' remote
packet reply. There should be only one such line in a single trace
file.
'tp PAYLOAD'
Tracepoint definition. The PAYLOAD has the same format as
'qTfP'/'qTsP' remote packet reply payload. A single tracepoint may
take multiple lines of definition, corresponding to the multiple
reply packets.
'tsv PAYLOAD'
Trace state variable definition. The PAYLOAD has the same format
as 'qTfV'/'qTsV' remote packet reply payload. A single variable
may take multiple lines of definition, corresponding to the
multiple reply packets.
'tdesc PAYLOAD'
Target description in XML format. The PAYLOAD is a single line of
the XML file. All such lines should be concatenated together to
get the original XML file. This file is in the same format as
'qXfer' 'features' payload, and corresponds to the main
'target.xml' file. Includes are not allowed.
The trace frame section consists of a number of consecutive frames.
Each frame begins with a two-byte tracepoint number, followed by a
four-byte size giving the amount of data in the frame. The data in the
frame consists of a number of blocks, each introduced by a character
indicating its type (at least register, memory, and trace state
variable). The data in this section is raw binary, not a hexadecimal or
other encoding; its endianness matches the target's endianness.
'R BYTES'
Register block. The number and ordering of bytes matches that of a
'g' packet in the remote protocol. Note that these are the actual
bytes, in target order, not a hexadecimal encoding.
'M ADDRESS LENGTH BYTES...'
Memory block. This is a contiguous block of memory, at the 8-byte
address ADDRESS, with a 2-byte length LENGTH, followed by LENGTH
bytes.
'V NUMBER VALUE'
Trace state variable block. This records the 8-byte signed value
VALUE of trace state variable numbered NUMBER.
Future enhancements of the trace file format may include additional
types of blocks.

File: gdb.info, Node: Index Section Format, Next: Man Pages, Prev: Trace File Format, Up: Top
Appendix J '.gdb_index' section format
**************************************
This section documents the index section that is created by 'save
gdb-index' (*note Index Files::). The index section is DWARF-specific;
some knowledge of DWARF is assumed in this description.
The mapped index file format is designed to be directly 'mmap'able on
any architecture. In most cases, a datum is represented using a
little-endian 32-bit integer value, called an 'offset_type'. Big endian
machines must byte-swap the values before using them. Exceptions to
this rule are noted. The data is laid out such that alignment is always
respected.
A mapped index consists of several areas, laid out in order.
1. The file header. This is a sequence of values, of 'offset_type'
unless otherwise noted:
1. The version number, currently 8. Versions 1, 2 and 3 are
obsolete. Version 4 uses a different hashing function from
versions 5 and 6. Version 6 includes symbols for inlined
functions, whereas versions 4 and 5 do not. Version 7 adds
attributes to the CU indices in the symbol table. Version 8
specifies that symbols from DWARF type units
('DW_TAG_type_unit') refer to the type unit's symbol table and
not the compilation unit ('DW_TAG_comp_unit') using the type.
GDB will only read version 4, 5, or 6 indices by specifying
'set use-deprecated-index-sections on'. GDB has a workaround
for potentially broken version 7 indices so it is currently
not flagged as deprecated.
2. The offset, from the start of the file, of the CU list.
3. The offset, from the start of the file, of the types CU list.
Note that this area can be empty, in which case this offset
will be equal to the next offset.
4. The offset, from the start of the file, of the address area.
5. The offset, from the start of the file, of the symbol table.
6. The offset, from the start of the file, of the constant pool.
2. The CU list. This is a sequence of pairs of 64-bit little-endian
values, sorted by the CU offset. The first element in each pair is
the offset of a CU in the '.debug_info' section. The second
element in each pair is the length of that CU. References to a CU
elsewhere in the map are done using a CU index, which is just the
0-based index into this table. Note that if there are type CUs,
then conceptually CUs and type CUs form a single list for the
purposes of CU indices.
3. The types CU list. This is a sequence of triplets of 64-bit
little-endian values. In a triplet, the first value is the CU
offset, the second value is the type offset in the CU, and the
third value is the type signature. The types CU list is not
sorted.
4. The address area. The address area consists of a sequence of
address entries. Each address entry has three elements:
1. The low address. This is a 64-bit little-endian value.
2. The high address. This is a 64-bit little-endian value. Like
'DW_AT_high_pc', the value is one byte beyond the end.
3. The CU index. This is an 'offset_type' value.
5. The symbol table. This is an open-addressed hash table. The size
of the hash table is always a power of 2.
Each slot in the hash table consists of a pair of 'offset_type'
values. The first value is the offset of the symbol's name in the
constant pool. The second value is the offset of the CU vector in
the constant pool.
If both values are 0, then this slot in the hash table is empty.
This is ok because while 0 is a valid constant pool index, it
cannot be a valid index for both a string and a CU vector.
The hash value for a table entry is computed by applying an
iterative hash function to the symbol's name. Starting with an
initial value of 'r = 0', each (unsigned) character 'c' in the
string is incorporated into the hash using the formula depending on
the index version:
Version 4
The formula is 'r = r * 67 + c - 113'.
Versions 5 to 7
The formula is 'r = r * 67 + tolower (c) - 113'.
The terminating '\0' is not incorporated into the hash.
The step size used in the hash table is computed via '((hash * 17)
& (size - 1)) | 1', where 'hash' is the hash value, and 'size' is
the size of the hash table. The step size is used to find the next
candidate slot when handling a hash collision.
The names of C++ symbols in the hash table are canonicalized. We
don't currently have a simple description of the canonicalization
algorithm; if you intend to create new index sections, you must
read the code.
6. The constant pool. This is simply a bunch of bytes. It is
organized so that alignment is correct: CU vectors are stored
first, followed by strings.
A CU vector in the constant pool is a sequence of 'offset_type'
values. The first value is the number of CU indices in the vector.
Each subsequent value is the index and symbol attributes of a CU in
the CU list. This element in the hash table is used to indicate
which CUs define the symbol and how the symbol is used. See below
for the format of each CU index+attributes entry.
A string in the constant pool is zero-terminated.
Attributes were added to CU index values in '.gdb_index' version 7.
If a symbol has multiple uses within a CU then there is one CU
index+attributes value for each use.
The format of each CU index+attributes entry is as follows (bit 0 =
LSB):
Bits 0-23
This is the index of the CU in the CU list.
Bits 24-27
These bits are reserved for future purposes and must be zero.
Bits 28-30
The kind of the symbol in the CU.
0
This value is reserved and should not be used. By reserving
zero the full 'offset_type' value is backwards compatible with
previous versions of the index.
1
The symbol is a type.
2
The symbol is a variable or an enum value.
3
The symbol is a function.
4
Any other kind of symbol.
5,6,7
These values are reserved.
Bit 31
This bit is zero if the value is global and one if it is static.
The determination of whether a symbol is global or static is
complicated. The authorative reference is the file 'dwarf2read.c'
in GDB sources.
This pseudo-code describes the computation of a symbol's kind and
global/static attributes in the index.
is_external = get_attribute (die, DW_AT_external);
language = get_attribute (cu_die, DW_AT_language);
switch (die->tag)
{
case DW_TAG_typedef:
case DW_TAG_base_type:
case DW_TAG_subrange_type:
kind = TYPE;
is_static = 1;
break;
case DW_TAG_enumerator:
kind = VARIABLE;
is_static = language != CPLUS;
break;
case DW_TAG_subprogram:
kind = FUNCTION;
is_static = ! (is_external || language == ADA);
break;
case DW_TAG_constant:
kind = VARIABLE;
is_static = ! is_external;
break;
case DW_TAG_variable:
kind = VARIABLE;
is_static = ! is_external;
break;
case DW_TAG_namespace:
kind = TYPE;
is_static = 0;
break;
case DW_TAG_class_type:
case DW_TAG_interface_type:
case DW_TAG_structure_type:
case DW_TAG_union_type:
case DW_TAG_enumeration_type:
kind = TYPE;
is_static = language != CPLUS;
break;
default:
assert (0);
}

File: gdb.info, Node: Man Pages, Next: Copying, Prev: Index Section Format, Up: Top
Appendix K Manual pages
***********************
* Menu:
* gdb man:: The GNU Debugger man page
* gdbserver man:: Remote Server for the GNU Debugger man page
* gcore man:: Generate a core file of a running program
* gdbinit man:: gdbinit scripts
* gdb-add-index man:: Add index files to speed up GDB

File: gdb.info, Node: gdb man, Next: gdbserver man, Up: Man Pages
gdb man
=======
gdb ['-help'] ['-nh'] ['-nx'] ['-q'] ['-batch'] ['-cd='DIR] ['-f']
['-b' BPS] ['-tty='DEV] ['-s' SYMFILE] ['-e' PROG] ['-se' PROG]
['-c' CORE] ['-p' PROCID] ['-x' CMDS] ['-d' DIR] [PROG|PROG PROCID|PROG
CORE]
The purpose of a debugger such as GDB is to allow you to see what is
going on "inside" another program while it executes - or what another
program was doing at the moment it crashed.
GDB can do four main kinds of things (plus other things in support of
these) to help you catch bugs in the act:
* Start your program, specifying anything that might affect its
behavior.
* Make your program stop on specified conditions.
* Examine what has happened, when your program has stopped.
* Change things in your program, so you can experiment with
correcting the effects of one bug and go on to learn about another.
You can use GDB to debug programs written in C, C++, Fortran and
Modula-2.
GDB is invoked with the shell command 'gdb'. Once started, it reads
commands from the terminal until you tell it to exit with the GDB
command 'quit'. You can get online help from GDB itself by using the
command 'help'.
You can run 'gdb' with no arguments or options; but the most usual
way to start GDB is with one argument or two, specifying an executable
program as the argument:
gdb program
You can also start with both an executable program and a core file
specified:
gdb program core
You can, instead, specify a process ID as a second argument or use
option '-p', if you want to debug a running process:
gdb program 1234
gdb -p 1234
would attach GDB to process '1234'. With option '-p' you can omit the
PROGRAM filename.
Here are some of the most frequently needed GDB commands:
'break [FILE:]FUNCTION'
Set a breakpoint at FUNCTION (in FILE).
'run [ARGLIST]'
Start your program (with ARGLIST, if specified).
'bt'
Backtrace: display the program stack.
'print EXPR'
Display the value of an expression.
'c'
Continue running your program (after stopping, e.g. at a
breakpoint).
'next'
Execute next program line (after stopping); step _over_ any
function calls in the line.
'edit [FILE:]FUNCTION'
look at the program line where it is presently stopped.
'list [FILE:]FUNCTION'
type the text of the program in the vicinity of where it is
presently stopped.
'step'
Execute next program line (after stopping); step _into_ any
function calls in the line.
'help [NAME]'
Show information about GDB command NAME, or general information
about using GDB.
'quit'
Exit from GDB.
Any arguments other than options specify an executable file and core
file (or process ID); that is, the first argument encountered with no
associated option flag is equivalent to a '-se' option, and the second,
if any, is equivalent to a '-c' option if it's the name of a file. Many
options have both long and short forms; both are shown here. The long
forms are also recognized if you truncate them, so long as enough of the
option is present to be unambiguous. (If you prefer, you can flag
option arguments with '+' rather than '-', though we illustrate the more
usual convention.)
All the options and command line arguments you give are processed in
sequential order. The order makes a difference when the '-x' option is
used.
'-help'
'-h'
List all options, with brief explanations.
'-symbols=FILE'
'-s FILE'
Read symbol table from file FILE.
'-write'
Enable writing into executable and core files.
'-exec=FILE'
'-e FILE'
Use file FILE as the executable file to execute when appropriate,
and for examining pure data in conjunction with a core dump.
'-se=FILE'
Read symbol table from file FILE and use it as the executable file.
'-core=FILE'
'-c FILE'
Use file FILE as a core dump to examine.
'-command=FILE'
'-x FILE'
Execute GDB commands from file FILE.
'-ex COMMAND'
Execute given GDB COMMAND.
'-directory=DIRECTORY'
'-d DIRECTORY'
Add DIRECTORY to the path to search for source files.
'-nh'
Do not execute commands from '~/.gdbinit'.
'-nx'
'-n'
Do not execute commands from any '.gdbinit' initialization files.
'-quiet'
'-q'
"Quiet". Do not print the introductory and copyright messages.
These messages are also suppressed in batch mode.
'-batch'
Run in batch mode. Exit with status '0' after processing all the
command files specified with '-x' (and '.gdbinit', if not
inhibited). Exit with nonzero status if an error occurs in
executing the GDB commands in the command files.
Batch mode may be useful for running GDB as a filter, for example
to download and run a program on another computer; in order to make
this more useful, the message
Program exited normally.
(which is ordinarily issued whenever a program running under GDB
control terminates) is not issued when running in batch mode.
'-cd=DIRECTORY'
Run GDB using DIRECTORY as its working directory, instead of the
current directory.
'-fullname'
'-f'
Emacs sets this option when it runs GDB as a subprocess. It tells
GDB to output the full file name and line number in a standard,
recognizable fashion each time a stack frame is displayed (which
includes each time the program stops). This recognizable format
looks like two '\032' characters, followed by the file name, line
number and character position separated by colons, and a newline.
The Emacs-to-GDB interface program uses the two '\032' characters
as a signal to display the source code for the frame.
'-b BPS'
Set the line speed (baud rate or bits per second) of any serial
interface used by GDB for remote debugging.
'-tty=DEVICE'
Run using DEVICE for your program's standard input and output.

File: gdb.info, Node: gdbserver man, Next: gcore man, Prev: gdb man, Up: Man Pages
gdbserver man
=============
gdbserver COMM PROG [ARGS...]
gdbserver -attach COMM PID
gdbserver -multi COMM
'gdbserver' is a program that allows you to run GDB on a different
machine than the one which is running the program being debugged.
Usage (server (target) side)
----------------------------
First, you need to have a copy of the program you want to debug put onto
the target system. The program can be stripped to save space if needed,
as 'gdbserver' doesn't care about symbols. All symbol handling is taken
care of by the GDB running on the host system.
To use the server, you log on to the target system, and run the
'gdbserver' program. You must tell it (a) how to communicate with GDB,
(b) the name of your program, and (c) its arguments. The general syntax
is:
target> gdbserver COMM PROGRAM [ARGS ...]
For example, using a serial port, you might say:
target> gdbserver /dev/com1 emacs foo.txt
This tells 'gdbserver' to debug emacs with an argument of foo.txt,
and to communicate with GDB via '/dev/com1'. 'gdbserver' now waits
patiently for the host GDB to communicate with it.
To use a TCP connection, you could say:
target> gdbserver host:2345 emacs foo.txt
This says pretty much the same thing as the last example, except that
we are going to communicate with the 'host' GDB via TCP. The 'host:2345'
argument means that we are expecting to see a TCP connection from 'host'
to local TCP port 2345. (Currently, the 'host' part is ignored.) You
can choose any number you want for the port number as long as it does
not conflict with any existing TCP ports on the target system. This
same port number must be used in the host GDBs 'target remote' command,
which will be described shortly. Note that if you chose a port number
that conflicts with another service, 'gdbserver' will print an error
message and exit.
'gdbserver' can also attach to running programs. This is
accomplished via the '--attach' argument. The syntax is:
target> gdbserver --attach COMM PID
PID is the process ID of a currently running process. It isn't
necessary to point 'gdbserver' at a binary for the running process.
To start 'gdbserver' without supplying an initial command to run or
process ID to attach, use the '--multi' command line option. In such
case you should connect using 'target extended-remote' to start the
program you want to debug.
target> gdbserver --multi COMM
Usage (host side)
-----------------
You need an unstripped copy of the target program on your host system,
since GDB needs to examine its symbol tables and such. Start up GDB as
you normally would, with the target program as the first argument. (You
may need to use the '--baud' option if the serial line is running at
anything except 9600 baud.) That is 'gdb TARGET-PROG', or 'gdb --baud
BAUD TARGET-PROG'. After that, the only new command you need to know
about is 'target remote' (or 'target extended-remote'). Its argument is
either a device name (usually a serial device, like '/dev/ttyb'), or a
'HOST:PORT' descriptor. For example:
(gdb) target remote /dev/ttyb
communicates with the server via serial line '/dev/ttyb', and:
(gdb) target remote the-target:2345
communicates via a TCP connection to port 2345 on host 'the-target',
where you previously started up 'gdbserver' with the same port number.
Note that for TCP connections, you must start up 'gdbserver' prior to
using the 'target remote' command, otherwise you may get an error that
looks something like 'Connection refused'.
'gdbserver' can also debug multiple inferiors at once, described in
*note Inferiors and Programs::. In such case use the 'extended-remote'
GDB command variant:
(gdb) target extended-remote the-target:2345
The 'gdbserver' option '--multi' may or may not be used in such case.
There are three different modes for invoking 'gdbserver':
* Debug a specific program specified by its program name:
gdbserver COMM PROG [ARGS...]
The COMM parameter specifies how should the server communicate with
GDB; it is either a device name (to use a serial line), a TCP port
number (':1234'), or '-' or 'stdio' to use stdin/stdout of
'gdbserver'. Specify the name of the program to debug in PROG.
Any remaining arguments will be passed to the program verbatim.
When the program exits, GDB will close the connection, and
'gdbserver' will exit.
* Debug a specific program by specifying the process ID of a running
program:
gdbserver --attach COMM PID
The COMM parameter is as described above. Supply the process ID of
a running program in PID; GDB will do everything else. Like with
the previous mode, when the process PID exits, GDB will close the
connection, and 'gdbserver' will exit.
* Multi-process mode - debug more than one program/process:
gdbserver --multi COMM
In this mode, GDB can instruct 'gdbserver' which command(s) to run.
Unlike the other 2 modes, GDB will not close the connection when a
process being debugged exits, so you can debug several processes in
the same session.
In each of the modes you may specify these options:
'--help'
List all options, with brief explanations.
'--version'
This option causes 'gdbserver' to print its version number and
exit.
'--attach'
'gdbserver' will attach to a running program. The syntax is:
target> gdbserver --attach COMM PID
PID is the process ID of a currently running process. It isn't
necessary to point 'gdbserver' at a binary for the running process.
'--multi'
To start 'gdbserver' without supplying an initial command to run or
process ID to attach, use this command line option. Then you can
connect using 'target extended-remote' and start the program you
want to debug. The syntax is:
target> gdbserver --multi COMM
'--debug'
Instruct 'gdbserver' to display extra status information about the
debugging process. This option is intended for 'gdbserver'
development and for bug reports to the developers.
'--remote-debug'
Instruct 'gdbserver' to display remote protocol debug output. This
option is intended for 'gdbserver' development and for bug reports
to the developers.
'--debug-file=FILENAME'
Instruct 'gdbserver' to send any debug output to the given
FILENAME. This option is intended for 'gdbserver' development and
for bug reports to the developers.
'--debug-format=option1[,option2,...]'
Instruct 'gdbserver' to include extra information in each line of
debugging output. *Note Other Command-Line Arguments for
gdbserver::.
'--wrapper'
Specify a wrapper to launch programs for debugging. The option
should be followed by the name of the wrapper, then any
command-line arguments to pass to the wrapper, then '--' indicating
the end of the wrapper arguments.
'--once'
By default, 'gdbserver' keeps the listening TCP port open, so that
additional connections are possible. However, if you start
'gdbserver' with the '--once' option, it will stop listening for
any further connection attempts after connecting to the first GDB
session.

File: gdb.info, Node: gcore man, Next: gdbinit man, Prev: gdbserver man, Up: Man Pages
gcore
=====
gcore [-a] [-o PREFIX] PID1 [PID2...PIDN]
Generate core dumps of one or more running programs with process IDs
PID1, PID2, etc. A core file produced by 'gcore' is equivalent to one
produced by the kernel when the process crashes (and when 'ulimit -c'
was used to set up an appropriate core dump limit). However, unlike
after a crash, after 'gcore' finishes its job the program remains
running without any change.
'-a'
Dump all memory mappings. The actual effect of this option depends
on the Operating System. On GNU/Linux, it will disable
'use-coredump-filter' (*note set use-coredump-filter::) and enable
'dump-excluded-mappings' (*note set dump-excluded-mappings::).
'-o PREFIX'
The optional argument PREFIX specifies the prefix to be used when
composing the file names of the core dumps. The file name is
composed as 'PREFIX.PID', where PID is the process ID of the
running program being analyzed by 'gcore'. If not specified,
PREFIX defaults to GCORE.

File: gdb.info, Node: gdbinit man, Next: gdb-add-index man, Prev: gcore man, Up: Man Pages
gdbinit
=======
~/.gdbinit
./.gdbinit
These files contain GDB commands to automatically execute during GDB
startup. The lines of contents are canned sequences of commands,
described in *note Sequences::.
Please read more in *note Startup::.
'(not enabled with --with-system-gdbinit during compilation)'
System-wide initialization file. It is executed unless user
specified GDB option '-nx' or '-n'. See more in
'(not enabled with --with-system-gdbinit-dir during compilation)'
System-wide initialization directory. All files in this directory
are executed on startup unless user specified GDB option '-nx' or
'-n', as long as they have a recognized file extension. See more
in *note System-wide configuration::.
'~/.gdbinit'
User initialization file. It is executed unless user specified GDB
options '-nx', '-n' or '-nh'.
'./.gdbinit'
Initialization file for current directory. It may need to be
enabled with GDB security command 'set auto-load local-gdbinit'.
See more in *note Init File in the Current Directory::.

File: gdb.info, Node: gdb-add-index man, Prev: gdbinit man, Up: Man Pages
gdb-add-index
=============
gdb-add-index FILENAME
When GDB finds a symbol file, it scans the symbols in the file in
order to construct an internal symbol table. This lets most GDB
operations work quickly-at the cost of a delay early on. For large
programs, this delay can be quite lengthy, so GDB provides a way to
build an index, which speeds up startup.
To determine whether a file contains such an index, use the command
'readelf -S filename': the index is stored in a section named
'.gdb_index'. The index file can only be produced on systems which use
ELF binaries and DWARF debug information (i.e., sections named
'.debug_*').
'gdb-add-index' uses GDB and 'objdump' found in the 'PATH'
environment variable. If you want to use different versions of these
programs, you can specify them through the 'GDB' and 'OBJDUMP'
environment variables.
See more in *note Index Files::.

File: gdb.info, Node: Copying, Next: GNU Free Documentation License, Prev: Man Pages, Up: Top
Appendix L GNU GENERAL PUBLIC LICENSE
*************************************
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
Preamble
========
The GNU General Public License is a free, copyleft license for software
and other kinds of works.
The licenses for most software and other practical works are designed
to take away your freedom to share and change the works. By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users. We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors. You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.
To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights. Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. You must make sure that they, too, receive
or can get the source code. And you must show them these terms so they
know their rights.
Developers that use the GNU GPL protect your rights with two steps:
(1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.
For the developers' and authors' protection, the GPL clearly explains
that there is no warranty for this free software. For both users' and
authors' sake, the GPL requires that modified versions be marked as
changed, so that their problems will not be attributed erroneously to
authors of previous versions.
Some devices are designed to deny users access to install or run
modified versions of the software inside them, although the manufacturer
can do so. This is fundamentally incompatible with the aim of
protecting users' freedom to change the software. The systematic
pattern of such abuse occurs in the area of products for individuals to
use, which is precisely where it is most unacceptable. Therefore, we
have designed this version of the GPL to prohibit the practice for those
products. If such problems arise substantially in other domains, we
stand ready to extend this provision to those domains in future versions
of the GPL, as needed to protect the freedom of users.
Finally, every program is threatened constantly by software patents.
States should not allow patents to restrict development and use of
software on general-purpose computers, but in those that do, we wish to
avoid the special danger that patents applied to a free program could
make it effectively proprietary. To prevent this, the GPL assures that
patents cannot be used to render the program non-free.
The precise terms and conditions for copying, distribution and
modification follow.
TERMS AND CONDITIONS
====================
0. Definitions.
"This License" refers to version 3 of the GNU General Public
License.
"Copyright" also means copyright-like laws that apply to other
kinds of works, such as semiconductor masks.
"The Program" refers to any copyrightable work licensed under this
License. Each licensee is addressed as "you". "Licensees" and
"recipients" may be individuals or organizations.
To "modify" a work means to copy from or adapt all or part of the
work in a fashion requiring copyright permission, other than the
making of an exact copy. The resulting work is called a "modified
version" of the earlier work or a work "based on" the earlier work.
A "covered work" means either the unmodified Program or a work
based on the Program.
To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on
a computer or modifying a private copy. Propagation includes
copying, distribution (with or without modification), making
available to the public, and in some countries other activities as
well.
To "convey" a work means any kind of propagation that enables other
parties to make or receive copies. Mere interaction with a user
through a computer network, with no transfer of a copy, is not
conveying.
An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to
the extent that warranties are provided), that licensees may convey
the work under this License, and how to view a copy of this
License. If the interface presents a list of user commands or
options, such as a menu, a prominent item in the list meets this
criterion.
1. Source Code.
The "source code" for a work means the preferred form of the work
for making modifications to it. "Object code" means any non-source
form of a work.
A "Standard Interface" means an interface that either is an
official standard defined by a recognized standards body, or, in
the case of interfaces specified for a particular programming
language, one that is widely used among developers working in that
language.
The "System Libraries" of an executable work include anything,
other than the work as a whole, that (a) is included in the normal
form of packaging a Major Component, but which is not part of that
Major Component, and (b) serves only to enable use of the work with
that Major Component, or to implement a Standard Interface for
which an implementation is available to the public in source code
form. A "Major Component", in this context, means a major
essential component (kernel, window system, and so on) of the
specific operating system (if any) on which the executable work
runs, or a compiler used to produce the work, or an object code
interpreter used to run it.
The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts
to control those activities. However, it does not include the
work's System Libraries, or general-purpose tools or generally
available free programs which are used unmodified in performing
those activities but which are not part of the work. For example,
Corresponding Source includes interface definition files associated
with source files for the work, and the source code for shared
libraries and dynamically linked subprograms that the work is
specifically designed to require, such as by intimate data
communication or control flow between those subprograms and other
parts of the work.
The Corresponding Source need not include anything that users can
regenerate automatically from other parts of the Corresponding
Source.
The Corresponding Source for a work in source code form is that
same work.
2. Basic Permissions.
All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met. This License explicitly affirms your unlimited
permission to run the unmodified Program. The output from running
a covered work is covered by this License only if the output, given
its content, constitutes a covered work. This License acknowledges
your rights of fair use or other equivalent, as provided by
copyright law.
You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise
remains in force. You may convey covered works to others for the
sole purpose of having them make modifications exclusively for you,
or provide you with facilities for running those works, provided
that you comply with the terms of this License in conveying all
material for which you do not control copyright. Those thus making
or running the covered works for you must do so exclusively on your
behalf, under your direction and control, on terms that prohibit
them from making any copies of your copyrighted material outside
their relationship with you.
Conveying under any other circumstances is permitted solely under
the conditions stated below. Sublicensing is not allowed; section
10 makes it unnecessary.
3. Protecting Users' Legal Rights From Anti-Circumvention Law.
No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under
article 11 of the WIPO copyright treaty adopted on 20 December
1996, or similar laws prohibiting or restricting circumvention of
such measures.
When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such
circumvention is effected by exercising rights under this License
with respect to the covered work, and you disclaim any intention to
limit operation or modification of the work as a means of
enforcing, against the work's users, your or third parties' legal
rights to forbid circumvention of technological measures.
4. Conveying Verbatim Copies.
You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the
code; keep intact all notices of the absence of any warranty; and
give all recipients a copy of this License along with the Program.
You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.
5. Conveying Modified Source Versions.
You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these
conditions:
a. The work must carry prominent notices stating that you
modified it, and giving a relevant date.
b. The work must carry prominent notices stating that it is
released under this License and any conditions added under
section 7. This requirement modifies the requirement in
section 4 to "keep intact all notices".
c. You must license the entire work, as a whole, under this
License to anyone who comes into possession of a copy. This
License will therefore apply, along with any applicable
section 7 additional terms, to the whole of the work, and all
its parts, regardless of how they are packaged. This License
gives no permission to license the work in any other way, but
it does not invalidate such permission if you have separately
received it.
d. If the work has interactive user interfaces, each must display
Appropriate Legal Notices; however, if the Program has
interactive interfaces that do not display Appropriate Legal
Notices, your work need not make them do so.
A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered
work, and which are not combined with it such as to form a larger
program, in or on a volume of a storage or distribution medium, is
called an "aggregate" if the compilation and its resulting
copyright are not used to limit the access or legal rights of the
compilation's users beyond what the individual works permit.
Inclusion of a covered work in an aggregate does not cause this
License to apply to the other parts of the aggregate.
6. Conveying Non-Source Forms.
You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this
License, in one of these ways:
a. Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by the
Corresponding Source fixed on a durable physical medium
customarily used for software interchange.
b. Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by a
written offer, valid for at least three years and valid for as
long as you offer spare parts or customer support for that
product model, to give anyone who possesses the object code
either (1) a copy of the Corresponding Source for all the
software in the product that is covered by this License, on a
durable physical medium customarily used for software
interchange, for a price no more than your reasonable cost of
physically performing this conveying of source, or (2) access
to copy the Corresponding Source from a network server at no
charge.
c. Convey individual copies of the object code with a copy of the
written offer to provide the Corresponding Source. This
alternative is allowed only occasionally and noncommercially,
and only if you received the object code with such an offer,
in accord with subsection 6b.
d. Convey the object code by offering access from a designated
place (gratis or for a charge), and offer equivalent access to
the Corresponding Source in the same way through the same
place at no further charge. You need not require recipients
to copy the Corresponding Source along with the object code.
If the place to copy the object code is a network server, the
Corresponding Source may be on a different server (operated by
you or a third party) that supports equivalent copying
facilities, provided you maintain clear directions next to the
object code saying where to find the Corresponding Source.
Regardless of what server hosts the Corresponding Source, you
remain obligated to ensure that it is available for as long as
needed to satisfy these requirements.
e. Convey the object code using peer-to-peer transmission,
provided you inform other peers where the object code and
Corresponding Source of the work are being offered to the
general public at no charge under subsection 6d.
A separable portion of the object code, whose source code is
excluded from the Corresponding Source as a System Library, need
not be included in conveying the object code work.
A "User Product" is either (1) a "consumer product", which means
any tangible personal property which is normally used for personal,
family, or household purposes, or (2) anything designed or sold for
incorporation into a dwelling. In determining whether a product is
a consumer product, doubtful cases shall be resolved in favor of
coverage. For a particular product received by a particular user,
"normally used" refers to a typical or common use of that class of
product, regardless of the status of the particular user or of the
way in which the particular user actually uses, or expects or is
expected to use, the product. A product is a consumer product
regardless of whether the product has substantial commercial,
industrial or non-consumer uses, unless such uses represent the
only significant mode of use of the product.
"Installation Information" for a User Product means any methods,
procedures, authorization keys, or other information required to
install and execute modified versions of a covered work in that
User Product from a modified version of its Corresponding Source.
The information must suffice to ensure that the continued
functioning of the modified object code is in no case prevented or
interfered with solely because modification has been made.
If you convey an object code work under this section in, or with,
or specifically for use in, a User Product, and the conveying
occurs as part of a transaction in which the right of possession
and use of the User Product is transferred to the recipient in
perpetuity or for a fixed term (regardless of how the transaction
is characterized), the Corresponding Source conveyed under this
section must be accompanied by the Installation Information. But
this requirement does not apply if neither you nor any third party
retains the ability to install modified object code on the User
Product (for example, the work has been installed in ROM).
The requirement to provide Installation Information does not
include a requirement to continue to provide support service,
warranty, or updates for a work that has been modified or installed
by the recipient, or for the User Product in which it has been
modified or installed. Access to a network may be denied when the
modification itself materially and adversely affects the operation
of the network or violates the rules and protocols for
communication across the network.
Corresponding Source conveyed, and Installation Information
provided, in accord with this section must be in a format that is
publicly documented (and with an implementation available to the
public in source code form), and must require no special password
or key for unpacking, reading or copying.
7. Additional Terms.
"Additional permissions" are terms that supplement the terms of
this License by making exceptions from one or more of its
conditions. Additional permissions that are applicable to the
entire Program shall be treated as though they were included in
this License, to the extent that they are valid under applicable
law. If additional permissions apply only to part of the Program,
that part may be used separately under those permissions, but the
entire Program remains governed by this License without regard to
the additional permissions.
When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part
of it. (Additional permissions may be written to require their own
removal in certain cases when you modify the work.) You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.
Notwithstanding any other provision of this License, for material
you add to a covered work, you may (if authorized by the copyright
holders of that material) supplement the terms of this License with
terms:
a. Disclaiming warranty or limiting liability differently from
the terms of sections 15 and 16 of this License; or
b. Requiring preservation of specified reasonable legal notices
or author attributions in that material or in the Appropriate
Legal Notices displayed by works containing it; or
c. Prohibiting misrepresentation of the origin of that material,
or requiring that modified versions of such material be marked
in reasonable ways as different from the original version; or
d. Limiting the use for publicity purposes of names of licensors
or authors of the material; or
e. Declining to grant rights under trademark law for use of some
trade names, trademarks, or service marks; or
f. Requiring indemnification of licensors and authors of that
material by anyone who conveys the material (or modified
versions of it) with contractual assumptions of liability to
the recipient, for any liability that these contractual
assumptions directly impose on those licensors and authors.
All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10. If the Program as
you received it, or any part of it, contains a notice stating that
it is governed by this License along with a term that is a further
restriction, you may remove that term. If a license document
contains a further restriction but permits relicensing or conveying
under this License, you may add to a covered work material governed
by the terms of that license document, provided that the further
restriction does not survive such relicensing or conveying.
If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.
Additional terms, permissive or non-permissive, may be stated in
the form of a separately written license, or stated as exceptions;
the above requirements apply either way.
8. Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights
under this License (including any patent licenses granted under the
third paragraph of section 11).
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from you
under this License. If your rights have been terminated and not
permanently reinstated, you do not qualify to receive new licenses
for the same material under section 10.
9. Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or
run a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer
transmission to receive a copy likewise does not require
acceptance. However, nothing other than this License grants you
permission to propagate or modify any covered work. These actions
infringe copyright if you do not accept this License. Therefore,
by modifying or propagating a covered work, you indicate your
acceptance of this License to do so.
10. Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not
responsible for enforcing compliance by third parties with this
License.
An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations. If propagation of a
covered work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or
could give under the previous paragraph, plus a right to possession
of the Corresponding Source of the work from the predecessor in
interest, if the predecessor has it or can get it with reasonable
efforts.
You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License. For example, you
may not impose a license fee, royalty, or other charge for exercise
of rights granted under this License, and you may not initiate
litigation (including a cross-claim or counterclaim in a lawsuit)
alleging that any patent claim is infringed by making, using,
selling, offering for sale, or importing the Program or any portion
of it.
11. Patents.
A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.
The work thus licensed is called the contributor's "contributor
version".
A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner,
permitted by this License, of making, using, or selling its
contributor version, but do not include claims that would be
infringed only as a consequence of further modification of the
contributor version. For purposes of this definition, "control"
includes the right to grant patent sublicenses in a manner
consistent with the requirements of this License.
Each contributor grants you a non-exclusive, worldwide,
royalty-free patent license under the contributor's essential
patent claims, to make, use, sell, offer for sale, import and
otherwise run, modify and propagate the contents of its contributor
version.
In the following three paragraphs, a "patent license" is any
express agreement or commitment, however denominated, not to
enforce a patent (such as an express permission to practice a
patent or covenant not to sue for patent infringement). To "grant"
such a patent license to a party means to make such an agreement or
commitment not to enforce a patent against the party.
If you convey a covered work, knowingly relying on a patent
license, and the Corresponding Source of the work is not available
for anyone to copy, free of charge and under the terms of this
License, through a publicly available network server or other
readily accessible means, then you must either (1) cause the
Corresponding Source to be so available, or (2) arrange to deprive
yourself of the benefit of the patent license for this particular
work, or (3) arrange, in a manner consistent with the requirements
of this License, to extend the patent license to downstream
recipients. "Knowingly relying" means you have actual knowledge
that, but for the patent license, your conveying the covered work
in a country, or your recipient's use of the covered work in a
country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate,
modify or convey a specific copy of the covered work, then the
patent license you grant is automatically extended to all
recipients of the covered work and works based on it.
A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that
are specifically granted under this License. You may not convey a
covered work if you are a party to an arrangement with a third
party that is in the business of distributing software, under which
you make payment to the third party based on the extent of your
activity of conveying the work, and under which the third party
grants, to any of the parties who would receive the covered work
from you, a discriminatory patent license (a) in connection with
copies of the covered work conveyed by you (or copies made from
those copies), or (b) primarily for and in connection with specific
products or compilations that contain the covered work, unless you
entered into that arrangement, or that patent license was granted,
prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.
12. No Surrender of Others' Freedom.
If conditions are imposed on you (whether by court order, agreement
or otherwise) that contradict the conditions of this License, they
do not excuse you from the conditions of this License. If you
cannot convey a covered work so as to satisfy simultaneously your
obligations under this License and any other pertinent obligations,
then as a consequence you may not convey it at all. For example,
if you agree to terms that obligate you to collect a royalty for
further conveying from those to whom you convey the Program, the
only way you could satisfy both those terms and this License would
be to refrain entirely from conveying the Program.
13. Use with the GNU Affero General Public License.
Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a
single combined work, and to convey the resulting work. The terms
of this License will continue to apply to the part which is the
covered work, but the special requirements of the GNU Affero
General Public License, section 13, concerning interaction through
a network will apply to the combination as such.
14. Revised Versions of this License.
The Free Software Foundation may publish revised and/or new
versions of the GNU General Public License from time to time. Such
new versions will be similar in spirit to the present version, but
may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the
Program specifies that a certain numbered version of the GNU
General Public License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that numbered version or of any later version published by the Free
Software Foundation. If the Program does not specify a version
number of the GNU General Public License, you may choose any
version ever published by the Free Software Foundation.
If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Program.
Later license versions may give you additional or different
permissions. However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.
15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE
RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.
SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR OR CORRECTION.
16. Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES
AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR
DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA
BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF
THE POSSIBILITY OF SUCH DAMAGES.
17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely
approximates an absolute waiver of all civil liability in
connection with the Program, unless a warranty or assumption of
liability accompanies a copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
===========================
How to Apply These Terms to Your New Programs
=============================================
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least the
"copyright" line and a pointer to where the full notice is found.
ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
Copyright (C) YEAR NAME OF AUTHOR
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper
mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
PROGRAM Copyright (C) YEAR NAME OF AUTHOR
This program comes with ABSOLUTELY NO WARRANTY; for details type 'show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'show c' for details.
The hypothetical commands 'show w' and 'show c' should show the
appropriate parts of the General Public License. Of course, your
program's commands might be different; for a GUI interface, you would
use an "about box".
You should also get your employer (if you work as a programmer) or
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. For more information on this, and how to apply and follow
the GNU GPL, see <http://www.gnu.org/licenses/>.
The GNU General Public License does not permit incorporating your
program into proprietary programs. If your program is a subroutine
library, you may consider it more useful to permit linking proprietary
applications with the library. If this is what you want to do, use the
GNU Lesser General Public License instead of this License. But first,
please read <http://www.gnu.org/philosophy/why-not-lgpl.html>.

File: gdb.info, Node: GNU Free Documentation License, Next: Concept Index, Prev: Copying, Up: Top
Appendix M GNU Free Documentation License
*****************************************
Version 1.3, 3 November 2008
Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book. We
recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it can
be distributed under the terms of this License. Such a notice
grants a world-wide, royalty-free license, unlimited in duration,
to use that work under the conditions stated herein. The
"Document", below, refers to any such manual or work. Any member
of the public is a licensee, and is addressed as "you". You accept
the license if you copy, modify or distribute the work in a way
requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could
fall directly within that overall subject. (Thus, if the Document
is in part a textbook of mathematics, a Secondary Section may not
explain any mathematics.) The relationship could be a matter of
historical connection with the subject or with related matters, or
of legal, commercial, philosophical, ethical or political position
regarding them.
The "Invariant Sections" are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License.
If a section does not fit the above definition of Secondary then it
is not allowed to be designated as Invariant. The Document may
contain zero Invariant Sections. If the Document does not identify
any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice
that says that the Document is released under this License. A
Front-Cover Text may be at most 5 words, and a Back-Cover Text may
be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed
of pixels) generic paint programs or (for drawings) some widely
available drawing editor, and that is suitable for input to text
formatters or for automatic translation to a variety of formats
suitable for input to text formatters. A copy made in an otherwise
Transparent file format whose markup, or absence of markup, has
been arranged to thwart or discourage subsequent modification by
readers is not Transparent. An image format is not Transparent if
used for any substantial amount of text. A copy that is not
"Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format,
SGML or XML using a publicly available DTD, and standard-conforming
simple HTML, PostScript or PDF designed for human modification.
Examples of transparent image formats include PNG, XCF and JPG.
Opaque formats include proprietary formats that can be read and
edited only by proprietary word processors, SGML or XML for which
the DTD and/or processing tools are not generally available, and
the machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For
works in formats which do not have any title page as such, "Title
Page" means the text near the most prominent appearance of the
work's title, preceding the beginning of the body of the text.
The "publisher" means any person or entity that distributes copies
of the Document to the public.
A section "Entitled XYZ" means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
stands for a specific section name mentioned below, such as
"Acknowledgements", "Dedications", "Endorsements", or "History".)
To "Preserve the Title" of such a section when you modify the
Document means that it remains a section "Entitled XYZ" according
to this definition.
The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow the
conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the title
equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as
long as they preserve the title of the Document and satisfy these
conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with
each Opaque copy a computer-network location from which the general
network-using public has access to download using public-standard
network protocols a complete Transparent copy of the Document, free
of added material. If you use the latter option, you must take
reasonably prudent steps, when you begin distribution of Opaque
copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or
through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies,
to give them a chance to provide you with an updated version of the
Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with the
Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever
possesses a copy of it. In addition, you must do these things in
the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of previous
versions (which should, if there were any, be listed in the
History section of the Document). You may use the same title
as a previous version if the original publisher of that
version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the
Title Page. If there is no section Entitled "History" in the
Document, create one stating the title, year, authors, and
publisher of the Document as given on its Title Page, then add
an item describing the Modified Version as stated in the
previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in the
"History" section. You may omit a network location for a work
that was published at least four years before the Document
itself, or if the original publisher of the version it refers
to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the section
all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered
in their text and in their titles. Section numbers or the
equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option designate
some or all of these sections as invariant. To do this, add their
titles to the list of Invariant Sections in the Modified Version's
license notice. These titles must be distinct from any other
section titles.
You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of
the list of Cover Texts in the Modified Version. Only one passage
of Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document
already includes a cover text for the same cover, previously added
by you or by arrangement made by the same entity you are acting on
behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added
the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination all
of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the documents
in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense, or distribute it is void,
and will automatically terminate your rights under this License.
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from you
under this License. If your rights have been terminated and not
permanently reinstated, receipt of a copy of some or all of the
same material does not give you any rights to use it.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
<http://www.gnu.org/copyleft/>.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may
choose any version ever published (not as a draft) by the Free
Software Foundation. If the Document specifies that a proxy can
decide which future versions of this License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Document.
11. RELICENSING
"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A
public wiki that anybody can edit is an example of such a server.
A "Massive Multiauthor Collaboration" (or "MMC") contained in the
site means any set of copyrightable works thus published on the MMC
site.
"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
"Incorporate" means to publish or republish a Document, in whole or
in part, as part of another Document.
An MMC is "eligible for relicensing" if it is licensed under this
License, and if all works that were first published under this
License somewhere other than this MMC, and subsequently
incorporated in whole or in part into the MMC, (1) had no cover
texts or invariant sections, and (2) were thus incorporated prior
to November 1, 2008.
The operator of an MMC Site may republish an MMC contained in the
site under CC-BY-SA on the same site at any time before August 1,
2009, provided the MMC is eligible for relicensing.
ADDENDUM: How to use this License for your documents
====================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.

File: gdb.info, Node: Concept Index, Next: Command and Variable Index, Prev: GNU Free Documentation License, Up: Top
Concept Index
*************
�[index�]
* Menu:
* ! packet: Packets. (line 49)
* "No symbol "foo" in current context": Variables. (line 122)
* # in Modula-2: GDB/M2. (line 18)
* $: Value History. (line 13)
* $$: Value History. (line 13)
* $_ and info breakpoints: Set Breaks. (line 133)
* $_ and info line: Machine Code. (line 34)
* $_, $__, and value history: Memory. (line 119)
* &, background execution of commands: Background Execution.
(line 16)
* --annotate: Mode Options. (line 132)
* --args: Mode Options. (line 145)
* --attach, gdbserver option: Server. (line 86)
* --batch: Mode Options. (line 55)
* --batch-silent: Mode Options. (line 73)
* --baud: Mode Options. (line 151)
* --cd: Mode Options. (line 112)
* --command: File Options. (line 51)
* --configuration: Mode Options. (line 195)
* --core: File Options. (line 43)
* --data-directory: Mode Options. (line 117)
* --debug, gdbserver option: Server. (line 146)
* --debug-file, gdbserver option: Server. (line 148)
* --debug-format, gdbserver option: Server. (line 153)
* --directory: File Options. (line 77)
* --eval-command: File Options. (line 57)
* --exec: File Options. (line 35)
* --fullname: Mode Options. (line 122)
* --init-command: File Options. (line 67)
* --init-eval-command: File Options. (line 72)
* --interpreter: Mode Options. (line 170)
* --multi, gdbserver option: Connecting. (line 45)
* --nh: Mode Options. (line 45)
* --nowindows: Mode Options. (line 102)
* --nx: Mode Options. (line 11)
* --once, gdbserver option: Server. (line 126)
* --pid: File Options. (line 47)
* --quiet: Mode Options. (line 51)
* --readnever, command-line option: File Options. (line 87)
* --readnow: File Options. (line 81)
* --remote-debug, gdbserver option: Server. (line 147)
* --return-child-result: Mode Options. (line 85)
* --se: File Options. (line 39)
* --selftest: Server. (line 187)
* --silent: Mode Options. (line 51)
* --statistics: Mode Options. (line 187)
* --symbols: File Options. (line 31)
* --tty: Mode Options. (line 160)
* --tui: Mode Options. (line 163)
* --version: Mode Options. (line 191)
* --windows: Mode Options. (line 108)
* --with-gdb-datadir: Data Files. (line 19)
* --with-relocated-sources: Source Path. (line 149)
* --with-sysroot: Files. (line 453)
* --wrapper, gdbserver option: Server. (line 166)
* --write: Mode Options. (line 182)
* -b: Mode Options. (line 151)
* -c: File Options. (line 43)
* -d: File Options. (line 77)
* -D: Mode Options. (line 117)
* -e: File Options. (line 35)
* -ex: File Options. (line 57)
* -f: Mode Options. (line 122)
* -iex: File Options. (line 72)
* -info-gdb-mi-command: GDB/MI Support Commands.
(line 14)
* -ix: File Options. (line 67)
* -l: Mode Options. (line 155)
* -n: Mode Options. (line 11)
* -nw: Mode Options. (line 102)
* -p: File Options. (line 47)
* -q: Mode Options. (line 51)
* -r: File Options. (line 81)
* -readnever, option for symbol-file command: Files. (line 101)
* -s: File Options. (line 31)
* -t: Mode Options. (line 160)
* -w: Mode Options. (line 108)
* -x: File Options. (line 51)
* ., Modula-2 scope operator: M2 Scope. (line 6)
* .build-id directory: Separate Debug Files.
(line 6)
* .debug subdirectories: Separate Debug Files.
(line 6)
* .debug_gdb_scripts section: dotdebug_gdb_scripts section.
(line 6)
* .gdbinit: Startup. (line 69)
* .gdb_index section: Index Files. (line 6)
* .gdb_index section format: Index Section Format.
(line 6)
* .gnu_debugdata section: MiniDebugInfo. (line 6)
* .gnu_debuglink sections: Separate Debug Files.
(line 79)
* .note.gnu.build-id sections: Separate Debug Files.
(line 95)
* .o files, reading symbols from: Files. (line 146)
* /proc: Process Information.
(line 6)
* <architecture>: Target Description Format.
(line 72)
* <compatible>: Target Description Format.
(line 95)
* <feature>: Target Description Format.
(line 119)
* <flags>: Target Description Format.
(line 163)
* <not saved> values: Registers. (line 106)
* <osabi>: Target Description Format.
(line 82)
* <reg>: Target Description Format.
(line 222)
* <struct>: Target Description Format.
(line 163)
* <union>: Target Description Format.
(line 153)
* <vector>: Target Description Format.
(line 146)
* ? packet: Packets. (line 58)
* _NSPrintForDebugger, and printing Objective-C objects: The Print Command with Objective-C.
(line 11)
* {TYPE}: Expressions. (line 41)
* A packet: Packets. (line 65)
* AArch64 Pointer Authentication.: AArch64. (line 34)
* AArch64 support: AArch64. (line 6)
* AArch64 SVE.: AArch64. (line 19)
* abbreviation: Command Syntax. (line 13)
* acknowledgment, for GDB remote: Packet Acknowledgment.
(line 6)
* active targets: Active Targets. (line 6)
* Ada: Ada. (line 6)
* Ada exception catching: Set Catchpoints. (line 66)
* Ada exception handlers catching: Set Catchpoints. (line 92)
* Ada mode, general: Ada Mode Intro. (line 6)
* Ada settings: Ada Settings. (line 6)
* Ada task switching: Ada Tasks. (line 115)
* Ada tasking and core file debugging: Ada Tasks and Core Files.
(line 6)
* Ada, deviations from: Additions to Ada. (line 6)
* Ada, omissions from: Omissions from Ada. (line 6)
* Ada, problems: Ada Glitches. (line 6)
* Ada, tasking: Ada Tasks. (line 6)
* add new commands for external monitor: Connecting. (line 272)
* address locations: Address Locations. (line 6)
* address of a symbol: Symbols. (line 85)
* address size for remote targets: Remote Configuration.
(line 12)
* addressable memory unit: Memory. (line 133)
* aggregates (Ada): Omissions from Ada. (line 44)
* AIX shared library debugging: Debugging Output. (line 30)
* AIX threads: Debugging Output. (line 36)
* aliases for commands: Aliases. (line 6)
* alignment of remote memory accesses: Packets. (line 247)
* all-stop mode: All-Stop Mode. (line 6)
* Alpha stack: MIPS. (line 6)
* ambiguous expressions: Ambiguous Expressions.
(line 6)
* annotations: Annotations Overview.
(line 6)
* annotations for errors, warnings and interrupts: Errors. (line 6)
* annotations for invalidation messages: Invalidation. (line 6)
* annotations for prompts: Prompting. (line 6)
* annotations for running programs: Annotations for Running.
(line 6)
* annotations for source display: Source Annotations. (line 6)
* append data to a file: Dump/Restore Files. (line 6)
* Application Data Integrity: Sparc64. (line 5)
* apply a command to all frames (ignoring errors and empty output): Frame Apply.
(line 96)
* apply a command to all frames of all threads (ignoring errors and empty output): Threads.
(line 229)
* apply command to all threads (ignoring errors and empty output): Threads.
(line 222)
* apply command to several frames: Frame Apply. (line 6)
* apply command to several threads: Threads. (line 187)
* ARC EM: ARC. (line 6)
* ARC HS: ARC. (line 6)
* ARC specific commands: ARC. (line 6)
* ARC600: ARC. (line 6)
* ARC700: ARC. (line 6)
* architecture debugging info: Debugging Output. (line 23)
* argument count in user-defined commands: Define. (line 25)
* arguments (to your program): Arguments. (line 6)
* arguments, to gdbserver: Server. (line 34)
* arguments, to user-defined commands: Define. (line 6)
* ARM 32-bit mode: ARM. (line 16)
* ARM AArch64: Debugging Output. (line 17)
* array aggregates (Ada): Omissions from Ada. (line 44)
* arrays: Arrays. (line 6)
* arrays in expressions: Expressions. (line 13)
* artificial array: Arrays. (line 6)
* assembly instructions: Machine Code. (line 43)
* assignment: Assignment. (line 6)
* async output in GDB/MI: GDB/MI Output Syntax.
(line 98)
* async records in GDB/MI: GDB/MI Async Records.
(line 6)
* asynchronous execution: Background Execution.
(line 6)
* asynchronous execution, and process record and replay: Process Record and Replay.
(line 101)
* AT&T disassembly flavor: Machine Code. (line 237)
* attach: Attach. (line 6)
* attach to a program, gdbserver: Server. (line 86)
* auto-loading: Auto-loading. (line 6)
* auto-loading extensions: Auto-loading extensions.
(line 6)
* auto-loading init file in the current directory: Init File in the Current Directory.
(line 6)
* auto-loading libthread_db.so.1: libthread_db.so.1 file.
(line 6)
* auto-loading safe-path: Auto-loading safe path.
(line 6)
* auto-loading verbose mode: Auto-loading verbose mode.
(line 6)
* auto-retry, for remote TCP target: Remote Configuration.
(line 131)
* automatic display: Auto Display. (line 6)
* automatic hardware breakpoints: Set Breaks. (line 296)
* automatic overlay debugging: Automatic Overlay Debugging.
(line 6)
* automatic symbol index cache: Index Files. (line 75)
* automatic thread selection: All-Stop Mode. (line 28)
* auxiliary vector: OS Information. (line 9)
* AVR: AVR. (line 6)
* b packet: Packets. (line 76)
* B packet: Packets. (line 91)
* background execution: Background Execution.
(line 6)
* backtrace beyond main function: Backtrace. (line 155)
* backtrace limit: Backtrace. (line 192)
* base name differences: Files. (line 520)
* baud rate for remote targets: Remote Configuration.
(line 21)
* bc packet: Packets. (line 96)
* bcache statistics: Maintenance Commands.
(line 328)
* bits in remote address: Remote Configuration.
(line 12)
* blocks in guile: Blocks In Guile. (line 6)
* blocks in python: Blocks In Python. (line 6)
* bookmark: Checkpoint/Restart. (line 6)
* boundary violations, Intel MPX: Signals. (line 197)
* branch trace configuration format: Branch Trace Configuration Format.
(line 6)
* branch trace format: Branch Trace Format.
(line 6)
* branch trace store: Process Record and Replay.
(line 70)
* break in overloaded functions: Debugging C Plus Plus.
(line 9)
* break on a system call.: Set Catchpoints. (line 120)
* break on fork/exec: Set Catchpoints. (line 116)
* BREAK signal instead of Ctrl-C: Remote Configuration.
(line 36)
* breakpoint address adjusted: Breakpoint-related Warnings.
(line 6)
* breakpoint at static probe point: Linespec Locations. (line 65)
* breakpoint commands: Break Commands. (line 6)
* breakpoint commands for GDB/MI: GDB/MI Breakpoint Commands.
(line 6)
* breakpoint commands, in remote protocol: General Query Packets.
(line 983)
* breakpoint conditions: Conditions. (line 6)
* breakpoint kinds, ARM: ARM Breakpoint Kinds.
(line 6)
* breakpoint kinds, MIPS: MIPS Breakpoint Kinds.
(line 6)
* breakpoint lists: Breakpoints. (line 45)
* breakpoint numbers: Breakpoints. (line 38)
* breakpoint on events: Breakpoints. (line 30)
* breakpoint on memory address: Breakpoints. (line 17)
* breakpoint on variable modification: Breakpoints. (line 17)
* breakpoint ranges: Breakpoints. (line 45)
* breakpoint subroutine, remote: Stub Contents. (line 31)
* breakpointing Ada elaboration code: Stopping Before Main Program.
(line 6)
* breakpoints: Breakpoints. (line 6)
* breakpoints and tasks, in Ada: Ada Tasks. (line 135)
* breakpoints and threads: Thread-Specific Breakpoints.
(line 10)
* breakpoints at functions matching a regexp: Set Breaks. (line 90)
* breakpoints in guile: Breakpoints In Guile.
(line 6)
* breakpoints in overlays: Overlay Commands. (line 91)
* breakpoints in python: Breakpoints In Python.
(line 6)
* breakpoints, multiple locations: Set Breaks. (line 200)
* bs packet: Packets. (line 102)
* bug criteria: Bug Criteria. (line 6)
* bug reports: Bug Reporting. (line 6)
* bugs in GDB: GDB Bugs. (line 6)
* build ID sections: Separate Debug Files.
(line 95)
* build ID, and separate debugging files: Separate Debug Files.
(line 6)
* building GDB, requirements for: Requirements. (line 6)
* built-in simulator target: Target Commands. (line 73)
* builtin Go functions: Go. (line 31)
* builtin Go types: Go. (line 28)
* C and C++: C. (line 6)
* C and C++ checks: C Checks. (line 6)
* C and C++ constants: C Constants. (line 6)
* C and C++ defaults: C Defaults. (line 6)
* C and C++ operators: C Operators. (line 6)
* c packet: Packets. (line 109)
* C packet: Packets. (line 118)
* C++: C. (line 10)
* C++ compilers: C Plus Plus Expressions.
(line 8)
* C++ demangling: Debugging C Plus Plus.
(line 36)
* C++ exception handling: Debugging C Plus Plus.
(line 20)
* C++ overload debugging info: Debugging Output. (line 147)
* C++ scope resolution: Variables. (line 90)
* C++ symbol decoding style: Print Settings. (line 529)
* C++ symbol display: Debugging C Plus Plus.
(line 40)
* caching data of targets: Caching Target Data.
(line 6)
* caching of bfd objects: File Caching. (line 6)
* caching of opened files: File Caching. (line 6)
* call dummy stack unwinding: Calling. (line 36)
* call dummy stack unwinding on unhandled exception.: Calling.
(line 47)
* call overloaded functions: C Plus Plus Expressions.
(line 26)
* call stack: Stack. (line 9)
* call stack traces: Backtrace. (line 6)
* call-clobbered registers: Registers. (line 106)
* caller-saved registers: Registers. (line 106)
* calling functions: Calling. (line 6)
* calling functions in the program, disabling: Calling. (line 59)
* calling make: Shell Commands. (line 21)
* case sensitivity in symbol names: Symbols. (line 27)
* case-insensitive symbol names: Symbols. (line 27)
* casts, in expressions: Expressions. (line 26)
* casts, to view memory: Expressions. (line 41)
* catch Ada exceptions: Set Catchpoints. (line 66)
* catch Ada exceptions when handled: Set Catchpoints. (line 92)
* catch syscalls from inferior, remote request: General Query Packets.
(line 401)
* catchpoints: Breakpoints. (line 30)
* catchpoints, setting: Set Catchpoints. (line 6)
* change GDB's working directory: Working Directory. (line 32)
* change inferior's working directory: Working Directory. (line 13)
* character sets: Character Sets. (line 6)
* charset: Character Sets. (line 6)
* checkpoint: Checkpoint/Restart. (line 6)
* checkpoints and process id: Checkpoint/Restart. (line 76)
* checks, range: Type Checking. (line 44)
* checks, type: Checks. (line 23)
* checksum, for GDB remote: Overview. (line 21)
* choosing target byte order: Byte Order. (line 6)
* circular trace buffer: Starting and Stopping Trace Experiments.
(line 80)
* clearing breakpoints, watchpoints, catchpoints: Delete Breaks.
(line 6)
* close, file-i/o system call: close. (line 6)
* closest symbol and offset for an address: Symbols. (line 95)
* code address and its source line: Machine Code. (line 28)
* code compression, MIPS: MIPS. (line 49)
* COFF/PE exported symbols: Debugging Output. (line 50)
* collected data discarded: Starting and Stopping Trace Experiments.
(line 6)
* colon, doubled as scope operator: M2 Scope. (line 6)
* colon-colon, context for variables/functions: Variables. (line 44)
* colors: Output Styling. (line 6)
* command editing: Readline Bare Essentials.
(line 6)
* command files: Command Files. (line 6)
* command history: Command History. (line 6)
* command hooks: Hooks. (line 6)
* command interpreters: Interpreters. (line 6)
* command line editing: Editing. (line 6)
* command options: Command Options. (line 6)
* command options, boolean: Command Options. (line 21)
* command options, raw input: Command Options. (line 13)
* command scripts, debugging: Messages/Warnings. (line 65)
* command tracing: Messages/Warnings. (line 60)
* commands for C++: Debugging C Plus Plus.
(line 6)
* commands in guile: Commands In Guile. (line 6)
* commands in python: Commands In Python. (line 6)
* commands to access guile: Guile Commands. (line 6)
* commands to access python: Python Commands. (line 6)
* comment: Command Syntax. (line 37)
* COMMON blocks, Fortran: Special Fortran Commands.
(line 9)
* common targets: Target Commands. (line 46)
* compatibility, GDB/MI and CLI: GDB/MI Compatibility with CLI.
(line 6)
* compilation directory: Source Path. (line 40)
* compile C++ type conversion: Compiling and Injecting Code.
(line 90)
* compile command debugging info: Compiling and Injecting Code.
(line 82)
* compile command driver filename override: Compiling and Injecting Code.
(line 300)
* compile command options override: Compiling and Injecting Code.
(line 125)
* compiling code: Compiling and Injecting Code.
(line 6)
* completion: Completion. (line 6)
* completion of Guile commands: Commands In Guile. (line 100)
* completion of Python commands: Commands In Python. (line 70)
* completion of quoted strings: Completion. (line 83)
* completion of structure field names: Completion. (line 135)
* completion of union field names: Completion. (line 135)
* compressed debug sections: Requirements. (line 110)
* conditional breakpoints: Conditions. (line 6)
* conditional tracepoints: Tracepoint Conditions.
(line 6)
* configuring GDB: Running Configure. (line 6)
* confirmation: Messages/Warnings. (line 49)
* connection timeout, for remote TCP target: Remote Configuration.
(line 147)
* console i/o as part of file-i/o: Console I/O. (line 6)
* console interpreter: Interpreters. (line 21)
* console output in GDB/MI: GDB/MI Output Syntax.
(line 106)
* constants, in file-i/o protocol: Constants. (line 6)
* continuing: Continuing and Stepping.
(line 6)
* continuing threads: Thread Stops. (line 6)
* control C, and remote debugging: Bootstrapping. (line 25)
* controlling terminal: Input/Output. (line 23)
* convenience functions: Convenience Funs. (line 6)
* convenience functions in python: Functions In Python.
(line 6)
* convenience variables: Convenience Vars. (line 6)
* convenience variables for tracepoints: Tracepoint Variables.
(line 6)
* convenience variables, and trace state variables: Trace State Variables.
(line 17)
* convenience variables, initializing: Convenience Vars. (line 42)
* core dump file: Files. (line 6)
* core dump file target: Target Commands. (line 54)
* crash of debugger: Bug Criteria. (line 9)
* CRC algorithm definition: Separate Debug Files.
(line 140)
* CRC of memory block, remote request: General Query Packets.
(line 65)
* CRIS: CRIS. (line 6)
* CRIS mode: CRIS. (line 26)
* CRIS version: CRIS. (line 10)
* Ctrl-BREAK, MS-Windows: Cygwin Native. (line 9)
* ctrl-c message, in file-i/o protocol: The Ctrl-C Message. (line 6)
* current Ada task ID: Ada Tasks. (line 105)
* current directory: Source Path. (line 40)
* current Go package: Go. (line 11)
* current thread: Threads. (line 29)
* current thread, remote request: General Query Packets.
(line 55)
* custom JIT debug info: Custom Debug Info. (line 6)
* Cygwin DLL, debugging: Cygwin Native. (line 60)
* Cygwin-specific commands: Cygwin Native. (line 6)
* D: D. (line 6)
* d packet: Packets. (line 127)
* D packet: Packets. (line 134)
* Darwin: Darwin. (line 6)
* data breakpoints: Breakpoints. (line 17)
* data manipulation, in GDB/MI: GDB/MI Data Manipulation.
(line 6)
* dcache line-size: Caching Target Data.
(line 60)
* dcache size: Caching Target Data.
(line 57)
* dead names, GNU Hurd: Hurd Native. (line 84)
* debug expression parser: Debugging Output. (line 152)
* debug formats and C++: C Plus Plus Expressions.
(line 8)
* debug link sections: Separate Debug Files.
(line 79)
* debug remote protocol: Debugging Output. (line 159)
* debugger crash: Bug Criteria. (line 9)
* debugging agent: In-Process Agent. (line 6)
* debugging C++ programs: C Plus Plus Expressions.
(line 8)
* debugging information directory, global: Separate Debug Files.
(line 6)
* debugging information in separate files: Separate Debug Files.
(line 6)
* debugging libthread_db: Threads. (line 331)
* debugging multiple processes: Forks. (line 55)
* debugging optimized code: Optimized Code. (line 6)
* debugging stub, example: Remote Stub. (line 6)
* debugging target: Targets. (line 6)
* debugging the Cygwin DLL: Cygwin Native. (line 60)
* decimal floating point format: Decimal Floating Point.
(line 6)
* default behavior of commands, changing: Command Settings. (line 6)
* default collection action: Tracepoint Actions. (line 142)
* default data directory: Data Files. (line 19)
* default settings, changing: Command Settings. (line 6)
* default source path substitution: Source Path. (line 149)
* default system root: Files. (line 453)
* define trace state variable, remote request: Tracepoint Packets.
(line 121)
* defining macros interactively: Macros. (line 59)
* definition of a macro, showing: Macros. (line 47)
* delete breakpoints: Delete Breaks. (line 41)
* deleting breakpoints, watchpoints, catchpoints: Delete Breaks.
(line 6)
* deliver a signal to a program: Signaling. (line 6)
* demangle: Symbols. (line 114)
* demangler crashes: Maintenance Commands.
(line 146)
* demangler crashes <1>: Maintenance Commands.
(line 173)
* demangler crashes <2>: Maintenance Commands.
(line 197)
* demangling C++ names: Print Settings. (line 510)
* deprecated commands: Maintenance Commands.
(line 160)
* derived type of an object, printing: Print Settings. (line 541)
* descriptor tables display: DJGPP Native. (line 24)
* detach from task, GNU Hurd: Hurd Native. (line 59)
* detach from thread, GNU Hurd: Hurd Native. (line 109)
* direct memory access (DMA) on MS-DOS: DJGPP Native. (line 74)
* directories for source files: Source Path. (line 6)
* directory, compilation: Source Path. (line 40)
* directory, current: Source Path. (line 40)
* disable address space randomization, remote request: General Query Packets.
(line 84)
* disabling calling functions in the program: Calling. (line 59)
* disassembler options: Machine Code. (line 222)
* disconnected tracing: Starting and Stopping Trace Experiments.
(line 45)
* displaced stepping debugging info: Debugging Output. (line 75)
* displaced stepping support: Maintenance Commands.
(line 112)
* displaced stepping, and process record and replay: Process Record and Replay.
(line 96)
* display command history: Command History. (line 95)
* display derived types: Print Settings. (line 541)
* display disabled out of scope: Auto Display. (line 86)
* display GDB copyright: Help. (line 158)
* display of expressions: Auto Display. (line 6)
* display remote monitor communications: Target Commands. (line 107)
* display remote packets: Debugging Output. (line 159)
* DJGPP debugging: DJGPP Native. (line 6)
* DLLs with no debugging symbols: Non-debug DLL Symbols.
(line 6)
* do not print frame arguments: Print Settings. (line 154)
* documentation: Formatting Documentation.
(line 22)
* don't repeat command: Define. (line 111)
* don't repeat Guile command: Commands In Guile. (line 67)
* don't repeat Python command: Commands In Python. (line 42)
* DOS file-name semantics of file names.: Files. (line 476)
* DOS serial data link, remote debugging: DJGPP Native. (line 118)
* DOS serial port status: DJGPP Native. (line 139)
* DPMI: DJGPP Native. (line 6)
* dprintf: Dynamic Printf. (line 6)
* dump all data collected at tracepoint: tdump. (line 6)
* dump core from inferior: Core File Generation.
(line 6)
* dump data to a file: Dump/Restore Files. (line 6)
* dump/restore files: Dump/Restore Files. (line 6)
* DVC register: PowerPC Embedded. (line 6)
* DWARF compilation units cache: Maintenance Commands.
(line 394)
* DWARF DIEs: Debugging Output. (line 56)
* DWARF frame unwinders: Maintenance Commands.
(line 408)
* DWARF Line Tables: Debugging Output. (line 61)
* DWARF Reading: Debugging Output. (line 68)
* DWARF-2 CFI and CRIS: CRIS. (line 18)
* dynamic linking: Files. (line 123)
* dynamic printf: Dynamic Printf. (line 6)
* dynamic varobj: GDB/MI Variable Objects.
(line 166)
* editing: Editing. (line 15)
* editing command lines: Readline Bare Essentials.
(line 6)
* editing source files: Edit. (line 6)
* eight-bit characters in strings: Print Settings. (line 455)
* elaboration phase: Starting. (line 92)
* ELinOS system-wide configuration script: System-wide Configuration Scripts.
(line 15)
* Emacs: Emacs. (line 6)
* empty response, for unsupported packets: Overview. (line 97)
* enable/disable a breakpoint: Disabling. (line 6)
* enabling and disabling probes: Static Probe Points.
(line 52)
* entering numbers: Numbers. (line 6)
* environment (of your program): Environment. (line 6)
* errno values, in file-i/o protocol: Errno Values. (line 6)
* error on valid input: Bug Criteria. (line 12)
* event debugging info: Debugging Output. (line 81)
* event designators: Event Designators. (line 6)
* event handling: Set Catchpoints. (line 6)
* examine process image: Process Information.
(line 6)
* examining data: Data. (line 6)
* examining memory: Memory. (line 9)
* exception handlers: Set Catchpoints. (line 6)
* exceptions, guile: Guile Exception Handling.
(line 6)
* exceptions, python: Exception Handling. (line 6)
* exec events, remote reply: Stop Reply Packets. (line 141)
* executable file: Files. (line 16)
* executable file target: Target Commands. (line 50)
* executable file, for remote target: Remote Configuration.
(line 102)
* execute commands from a file: Command Files. (line 17)
* execute forward or backward in time: Reverse Execution. (line 92)
* execute remote command, remote request: General Query Packets.
(line 536)
* execution, foreground, background and asynchronous: Background Execution.
(line 6)
* exit status of shell commands: Convenience Vars. (line 187)
* exiting GDB: Quitting GDB. (line 6)
* expand macro once: Macros. (line 38)
* expanding preprocessor macros: Macros. (line 29)
* explicit locations: Explicit Locations. (line 6)
* explore type: Data. (line 234)
* explore value: Data. (line 227)
* exploring hierarchical data structures: Data. (line 125)
* expression debugging info: Debugging Output. (line 86)
* expression parser, debugging info: Debugging Output. (line 152)
* expressions: Expressions. (line 6)
* expressions in Ada: Ada. (line 11)
* expressions in C or C++: C. (line 6)
* expressions in C++: C Plus Plus Expressions.
(line 6)
* expressions in Modula-2: Modula-2. (line 12)
* extend GDB for remote targets: Connecting. (line 272)
* extending GDB: Extending GDB. (line 6)
* extra signal information: Signals. (line 156)
* F packet: Packets. (line 150)
* F reply packet: The F Reply Packet. (line 6)
* F request packet: The F Request Packet.
(line 6)
* fast tracepoints: Set Tracepoints. (line 24)
* fast tracepoints, setting: Create and Delete Tracepoints.
(line 50)
* fatal signal: Bug Criteria. (line 9)
* fatal signals: Signals. (line 15)
* features of the remote protocol: General Query Packets.
(line 589)
* file name canonicalization: Files. (line 520)
* file transfer: File Transfer. (line 6)
* file transfer, remote protocol: Host I/O Packets. (line 6)
* file-i/o examples: File-I/O Examples. (line 6)
* file-i/o overview: File-I/O Overview. (line 6)
* File-I/O remote protocol extension: File-I/O Remote Protocol Extension.
(line 6)
* file-i/o reply packet: The F Reply Packet. (line 6)
* file-i/o request packet: The F Request Packet.
(line 6)
* filename-display: Backtrace. (line 202)
* find trace snapshot: tfind. (line 6)
* flinching: Messages/Warnings. (line 49)
* float promotion: ABI. (line 34)
* floating point: Floating Point Hardware.
(line 6)
* floating point registers: Registers. (line 15)
* floating point, MIPS remote: MIPS Embedded. (line 13)
* focus of debugging: Threads. (line 29)
* foo: Symbol Errors. (line 54)
* foreground execution: Background Execution.
(line 6)
* fork events, remote reply: Stop Reply Packets. (line 104)
* fork, debugging programs which call: Forks. (line 6)
* format options: Print Settings. (line 6)
* formatted output: Output Formats. (line 6)
* Fortran: Summary. (line 40)
* Fortran Defaults: Fortran Defaults. (line 6)
* Fortran modules, information about: Symbols. (line 555)
* Fortran operators and expressions: Fortran Operators. (line 6)
* Fortran-specific support in GDB: Fortran. (line 6)
* FR-V shared-library debugging: Debugging Output. (line 193)
* frame debugging info: Debugging Output. (line 101)
* frame decorator api: Frame Decorator API.
(line 6)
* frame filters api: Frame Filter API. (line 6)
* frame information, printing: Print Settings. (line 314)
* frame level: Frames. (line 28)
* frame number: Frames. (line 28)
* frame pointer: Frames. (line 21)
* frame pointer register: Registers. (line 31)
* frame, definition: Frames. (line 6)
* frameless execution: Frames. (line 34)
* frames in guile: Frames In Guile. (line 6)
* frames in python: Frames In Python. (line 6)
* free memory information (MS-DOS): DJGPP Native. (line 19)
* FreeBSD: FreeBSD. (line 6)
* FreeBSD LWP debug messages: Debugging Output. (line 92)
* FreeBSD native target debug messages: Debugging Output. (line 97)
* fstat, file-i/o system call: stat/fstat. (line 6)
* Fujitsu: Remote Stub. (line 68)
* full symbol tables, listing GDB's internal: Symbols. (line 645)
* function call arguments, optimized out: Backtrace. (line 133)
* function entry/exit, wrong values of variables: Variables. (line 106)
* functions and variables by Fortran module: Symbols. (line 555)
* functions without line info, and stepping: Continuing and Stepping.
(line 92)
* g packet: Packets. (line 155)
* G packet: Packets. (line 183)
* g++, GNU C++ compiler: C. (line 10)
* garbled pointers: DJGPP Native. (line 42)
* GCC and C++: C Plus Plus Expressions.
(line 8)
* GDB bugs, reporting: Bug Reporting. (line 6)
* GDB internal error: Maintenance Commands.
(line 197)
* gdb module: Basic Python. (line 28)
* gdb objects: GDB Scheme Data Types.
(line 6)
* GDB reference card: Formatting Documentation.
(line 6)
* GDB startup: Startup. (line 6)
* GDB version number: Help. (line 148)
* gdb.ini: Startup. (line 69)
* gdb.printing: gdb.printing. (line 6)
* gdb.prompt: gdb.prompt. (line 6)
* gdb.types: gdb.types. (line 6)
* gdb.Value: Values From Inferior.
(line 6)
* GDB/MI development: GDB/MI Development and Front Ends.
(line 6)
* GDB/MI General Design: GDB/MI General Design.
(line 6)
* GDB/MI, async records: GDB/MI Async Records.
(line 6)
* GDB/MI, breakpoint commands: GDB/MI Breakpoint Commands.
(line 6)
* GDB/MI, compatibility with CLI: GDB/MI Compatibility with CLI.
(line 6)
* GDB/MI, data manipulation: GDB/MI Data Manipulation.
(line 6)
* GDB/MI, input syntax: GDB/MI Input Syntax.
(line 6)
* GDB/MI, its purpose: GDB/MI. (line 36)
* GDB/MI, output syntax: GDB/MI Output Syntax.
(line 6)
* GDB/MI, result records: GDB/MI Result Records.
(line 6)
* GDB/MI, simple examples: GDB/MI Simple Examples.
(line 6)
* GDB/MI, stream records: GDB/MI Stream Records.
(line 6)
* gdbarch debugging info: Debugging Output. (line 23)
* GDBHISTFILE, environment variable: Command History. (line 26)
* GDBHISTSIZE, environment variable: Command History. (line 45)
* gdbserver, command-line arguments: Server. (line 34)
* gdbserver, connecting: Connecting. (line 6)
* gdbserver, search path for libthread_db: Server. (line 254)
* gdbserver, send all debug output to a single file: Server. (line 148)
* gdbserver, target extended-remote mode: Connecting. (line 6)
* gdbserver, target remote mode: Connecting. (line 6)
* gdbserver, types of connections: Connecting. (line 6)
* GDT: DJGPP Native. (line 24)
* get thread information block address: General Query Packets.
(line 303)
* get thread-local storage address, remote request: General Query Packets.
(line 271)
* gettimeofday, file-i/o system call: gettimeofday. (line 6)
* getting structure elements using gdb.Field objects as subscripts: Values From Inferior.
(line 40)
* global debugging information directories: Separate Debug Files.
(line 6)
* global thread identifier (GDB): Threads. (line 88)
* global thread number: Threads. (line 88)
* GNAT descriptive types: Ada Glitches. (line 57)
* GNAT encoding: Ada Glitches. (line 57)
* GNU C++: C. (line 10)
* GNU Emacs: Emacs. (line 6)
* GNU Hurd debugging: Hurd Native. (line 6)
* GNU/Hurd debug messages: Debugging Output. (line 106)
* GNU/Linux LWP debug messages: Debugging Output. (line 121)
* GNU/Linux namespaces debug messages: Debugging Output. (line 125)
* Go (programming language): Go. (line 6)
* guile api: Guile API. (line 6)
* guile architectures: Architectures In Guile.
(line 6)
* guile auto-loading: Guile Auto-loading. (line 6)
* guile commands: Guile Commands. (line 6)
* guile commands <1>: Commands In Guile. (line 6)
* guile configuration: Guile Configuration.
(line 6)
* guile exceptions: Guile Exception Handling.
(line 6)
* guile gdb module: Basic Guile. (line 37)
* guile iterators: Iterators In Guile. (line 6)
* guile modules: Guile Modules. (line 6)
* guile pagination: Basic Guile. (line 6)
* guile parameters: Parameters In Guile.
(line 6)
* guile pretty printing api: Guile Pretty Printing API.
(line 6)
* guile scripting: Guile. (line 6)
* guile scripts directory: Guile Introduction. (line 16)
* guile stdout: Basic Guile. (line 6)
* guile, working with types: Types In Guile. (line 6)
* guile, working with values from inferior: Values From Inferior In Guile.
(line 6)
* H packet: Packets. (line 193)
* handling signals: Signals. (line 27)
* hardware breakpoints: Set Breaks. (line 61)
* hardware debug registers: Maintenance Commands.
(line 454)
* hardware watchpoints: Set Watchpoints. (line 31)
* hash mark while downloading: Target Commands. (line 98)
* heuristic-fence-post (Alpha, MIPS): MIPS. (line 14)
* history events: Event Designators. (line 8)
* history expansion: History Interaction.
(line 6)
* history expansion, turn on/off: Command History. (line 70)
* history file: Command History. (line 26)
* history number: Value History. (line 13)
* history of values printed by GDB: Value History. (line 6)
* history size: Command History. (line 45)
* history substitution: Command History. (line 26)
* hooks, for commands: Hooks. (line 6)
* hooks, post-command: Hooks. (line 11)
* hooks, pre-command: Hooks. (line 6)
* host character set: Character Sets. (line 6)
* Host I/O, remote protocol: Host I/O Packets. (line 6)
* how many arguments (user-defined commands): Define. (line 25)
* HPPA support: HPPA. (line 6)
* i packet: Packets. (line 207)
* I packet: Packets. (line 212)
* i/o: Input/Output. (line 6)
* I/O registers (Atmel AVR): AVR. (line 10)
* i386: Remote Stub. (line 56)
* i386-stub.c: Remote Stub. (line 56)
* IDT: DJGPP Native. (line 24)
* ignore count (of breakpoint): Conditions. (line 79)
* in-process agent protocol: In-Process Agent Protocol.
(line 6)
* incomplete type: Symbols. (line 346)
* indentation in structure display: Print Settings. (line 417)
* index files: Index Files. (line 6)
* index section format: Index Section Format.
(line 6)
* inferior: Inferiors and Programs.
(line 13)
* inferior debugging info: Debugging Output. (line 110)
* inferior events in Python: Events In Python. (line 6)
* inferior functions, calling: Calling. (line 6)
* inferior tty: Input/Output. (line 44)
* inferiors in Python: Inferiors In Python.
(line 6)
* infinite recursion in user-defined commands: Define. (line 128)
* info for known .debug_gdb_scripts-loaded scripts: Maintenance Commands.
(line 321)
* info for known object files: Maintenance Commands.
(line 306)
* info line, repeated calls: Machine Code. (line 40)
* info proc cmdline: Process Information.
(line 41)
* info proc cwd: Process Information.
(line 45)
* info proc exe: Process Information.
(line 49)
* info proc files: Process Information.
(line 53)
* information about static tracepoint markers: Listing Static Tracepoint Markers.
(line 6)
* information about tracepoints: Listing Tracepoints.
(line 6)
* inheritance: Debugging C Plus Plus.
(line 26)
* init file: Startup. (line 11)
* init file name: Startup. (line 69)
* initial frame: Frames. (line 12)
* initialization file, readline: Readline Init File. (line 6)
* injecting code: Compiling and Injecting Code.
(line 6)
* inline functions, debugging: Inline Functions. (line 6)
* innermost frame: Frames. (line 12)
* input syntax for GDB/MI: GDB/MI Input Syntax.
(line 6)
* installation: Installing GDB. (line 6)
* instructions, assembly: Machine Code. (line 43)
* integral datatypes, in file-i/o protocol: Integral Datatypes.
(line 6)
* Intel: Remote Stub. (line 56)
* Intel disassembly flavor: Machine Code. (line 237)
* Intel Memory Protection Extensions (MPX).: i386. (line 21)
* Intel MPX boundary violations: Signals. (line 197)
* Intel Processor Trace: Process Record and Replay.
(line 75)
* interaction, readline: Readline Interaction.
(line 6)
* internal commands: Maintenance Commands.
(line 6)
* internal errors, control of GDB behavior: Maintenance Commands.
(line 197)
* internal GDB breakpoints: Set Breaks. (line 374)
* interrupt: Quitting GDB. (line 13)
* interrupt debuggee on MS-Windows: Cygwin Native. (line 9)
* interrupt remote programs: Remote Configuration.
(line 36)
* interrupt remote programs <1>: Remote Configuration.
(line 108)
* interrupting remote programs: Connecting. (line 239)
* interrupting remote targets: Bootstrapping. (line 25)
* interrupts (remote protocol): Interrupts. (line 6)
* invalid input: Bug Criteria. (line 16)
* invoke another interpreter: Interpreters. (line 39)
* ipa protocol commands: IPA Protocol Commands.
(line 6)
* ipa protocol objects: IPA Protocol Objects.
(line 6)
* isatty, file-i/o system call: isatty. (line 6)
* JIT compilation interface: JIT Interface. (line 6)
* JIT debug info reader: Custom Debug Info. (line 6)
* just-in-time compilation: JIT Interface. (line 6)
* just-in-time compilation, debugging messages: Debugging Output.
(line 117)
* k packet: Packets. (line 216)
* kernel crash dump: BSD libkvm Interface.
(line 6)
* kernel memory image: BSD libkvm Interface.
(line 6)
* kill ring: Readline Killing Commands.
(line 18)
* killing text: Readline Killing Commands.
(line 6)
* languages: Languages. (line 6)
* last tracepoint number: Create and Delete Tracepoints.
(line 122)
* latest breakpoint: Set Breaks. (line 6)
* lazy strings in guile: Lazy Strings In Guile.
(line 6)
* lazy strings in python: Lazy Strings In Python.
(line 6)
* LDT: DJGPP Native. (line 24)
* leaving GDB: Quitting GDB. (line 6)
* libkvm: BSD libkvm Interface.
(line 6)
* library list format, remote protocol: Library List Format.
(line 6)
* library list format, remote protocol <1>: Library List Format for SVR4 Targets.
(line 6)
* limit hardware breakpoints and watchpoints: Remote Configuration.
(line 79)
* limit hardware watchpoints length: Remote Configuration.
(line 91)
* limit on number of printed array elements: Print Settings. (line 141)
* limits, in file-i/o protocol: Limits. (line 6)
* line tables in python: Line Tables In Python.
(line 6)
* line tables, listing GDB's internal: Symbols. (line 692)
* linespec locations: Linespec Locations. (line 6)
* Linux lightweight processes: Debugging Output. (line 121)
* list active threads, remote request: General Query Packets.
(line 238)
* list of supported file-i/o calls: List of Supported Calls.
(line 6)
* list output in GDB/MI: GDB/MI Output Syntax.
(line 117)
* list, how many lines to display: List. (line 30)
* listing GDB's internal line tables: Symbols. (line 692)
* listing GDB's internal symbol tables: Symbols. (line 645)
* listing machine instructions: Machine Code. (line 43)
* listing mapped overlays: Overlay Commands. (line 60)
* lists of breakpoints: Breakpoints. (line 45)
* load address, overlay's: How Overlays Work. (line 6)
* load shared library: Files. (line 327)
* load symbols from memory: Files. (line 193)
* local socket, target remote: Connecting. (line 140)
* local variables: Symbols. (line 415)
* locate address: Output Formats. (line 35)
* location: Specify Location. (line 6)
* lock scheduler: All-Stop Mode. (line 37)
* log output in GDB/MI: GDB/MI Output Syntax.
(line 113)
* logging file name: Logging Output. (line 12)
* logging GDB output: Logging Output. (line 6)
* lseek flags, in file-i/o protocol: Lseek Flags. (line 6)
* lseek, file-i/o system call: lseek. (line 6)
* m packet: Packets. (line 239)
* M packet: Packets. (line 259)
* m680x0: Remote Stub. (line 59)
* m68k-stub.c: Remote Stub. (line 59)
* Mach-O symbols processing: Debugging Output. (line 130)
* machine instructions: Machine Code. (line 43)
* macro definition, showing: Macros. (line 47)
* macro expansion, showing the results of preprocessor: Macros.
(line 29)
* macros, example of debugging with: Macros. (line 83)
* macros, from debug info: Macros. (line 47)
* macros, user-defined: Macros. (line 59)
* mailing lists: GDB/MI Development and Front Ends.
(line 78)
* maintenance commands: Maintenance Commands.
(line 6)
* Man pages: Man Pages. (line 6)
* managing frame filters: Frame Filter Management.
(line 6)
* manual overlay debugging: Overlay Commands. (line 23)
* map an overlay: Overlay Commands. (line 30)
* mapinfo list, QNX Neutrino: Process Information.
(line 130)
* mapped address: How Overlays Work. (line 6)
* mapped overlays: How Overlays Work. (line 6)
* markers, static tracepoints: Set Tracepoints. (line 28)
* maximum value for offset of closest symbol: Print Settings.
(line 70)
* member functions: C Plus Plus Expressions.
(line 16)
* memory address space mappings: Process Information.
(line 80)
* memory map format: Memory Map Format. (line 6)
* memory region attributes: Memory Region Attributes.
(line 6)
* memory tracing: Breakpoints. (line 17)
* memory transfer, in file-i/o protocol: Memory Transfer. (line 6)
* memory used by commands: Maintenance Commands.
(line 555)
* memory used for symbol tables: Files. (line 315)
* memory, alignment and size of remote accesses: Packets. (line 247)
* memory, viewing as typed object: Expressions. (line 41)
* mi interpreter: Interpreters. (line 26)
* mi1 interpreter: Interpreters. (line 37)
* mi2 interpreter: Interpreters. (line 34)
* mi3 interpreter: Interpreters. (line 31)
* minimal language: Unsupported Languages.
(line 6)
* minimal symbol dump: Symbols. (line 619)
* Minimal symbols and DLLs: Non-debug DLL Symbols.
(line 6)
* MIPS addresses, masking: MIPS. (line 80)
* MIPS remote floating point: MIPS Embedded. (line 13)
* MIPS stack: MIPS. (line 6)
* miscellaneous settings: Other Misc Settings.
(line 6)
* MMX registers (x86): Registers. (line 76)
* mode_t values, in file-i/o protocol: mode_t Values. (line 6)
* Modula-2: Summary. (line 29)
* Modula-2 built-ins: Built-In Func/Proc. (line 6)
* Modula-2 checks: M2 Checks. (line 6)
* Modula-2 constants: Built-In Func/Proc. (line 114)
* Modula-2 defaults: M2 Defaults. (line 6)
* Modula-2 operators: M2 Operators. (line 6)
* Modula-2 types: M2 Types. (line 6)
* Modula-2, deviations from: Deviations. (line 6)
* Modula-2, GDB support: Modula-2. (line 6)
* module functions and variables: Symbols. (line 555)
* modules: Symbols. (line 547)
* monitor commands, for gdbserver: Server. (line 218)
* Motorola 680x0: Remote Stub. (line 59)
* MS Windows debugging: Cygwin Native. (line 6)
* MS-DOS system info: DJGPP Native. (line 19)
* MS-DOS-specific commands: DJGPP Native. (line 6)
* multiple locations, breakpoints: Set Breaks. (line 200)
* multiple processes: Forks. (line 6)
* multiple targets: Active Targets. (line 6)
* multiple threads: Threads. (line 6)
* multiple threads, backtrace: Backtrace. (line 97)
* multiple-symbols menu: Ambiguous Expressions.
(line 51)
* multiprocess extensions, in remote protocol: General Query Packets.
(line 913)
* name a thread: Threads. (line 247)
* names of symbols: Symbols. (line 14)
* namespace in C++: C Plus Plus Expressions.
(line 20)
* native Cygwin debugging: Cygwin Native. (line 6)
* native DJGPP debugging: DJGPP Native. (line 6)
* native script auto-loading: Auto-loading sequences.
(line 6)
* native target: Target Commands. (line 85)
* negative breakpoint numbers: Set Breaks. (line 374)
* never read symbols: Files. (line 101)
* New SYSTAG message: Threads. (line 35)
* new user interface: Interpreters. (line 68)
* Newlib OS ABI and its influence on the longjmp handling: ABI.
(line 11)
* Nios II architecture: Nios II. (line 6)
* no debug info functions: Calling. (line 78)
* no debug info variables: Variables. (line 142)
* non-member C++ functions, set breakpoint in: Set Breaks. (line 113)
* non-stop mode: Non-Stop Mode. (line 6)
* non-stop mode, and process record and replay: Process Record and Replay.
(line 101)
* non-stop mode, and set displaced-stepping: Maintenance Commands.
(line 129)
* non-stop mode, remote request: General Query Packets.
(line 379)
* noninvasive task options: Hurd Native. (line 72)
* notation, readline: Readline Bare Essentials.
(line 6)
* notational conventions, for GDB/MI: GDB/MI. (line 52)
* notification packets: Notification Packets.
(line 6)
* notify output in GDB/MI: GDB/MI Output Syntax.
(line 102)
* NULL elements in arrays: Print Settings. (line 408)
* number of array elements to print: Print Settings. (line 141)
* number representation: Numbers. (line 6)
* numbers for breakpoints: Breakpoints. (line 38)
* object files, relocatable, reading symbols from: Files. (line 146)
* Objective-C: Objective-C. (line 6)
* Objective-C, classes and selectors: Symbols. (line 570)
* Objective-C, print objects: The Print Command with Objective-C.
(line 6)
* OBJFILE-gdb.gdb: objfile-gdbdotext file.
(line 6)
* OBJFILE-gdb.py: objfile-gdbdotext file.
(line 6)
* OBJFILE-gdb.scm: objfile-gdbdotext file.
(line 6)
* objfiles in guile: Objfiles In Guile. (line 6)
* objfiles in python: Objfiles In Python. (line 6)
* observer debugging info: Debugging Output. (line 142)
* octal escapes in strings: Print Settings. (line 455)
* online documentation: Help. (line 6)
* opaque data types: Symbols. (line 582)
* open flags, in file-i/o protocol: Open Flags. (line 6)
* open, file-i/o system call: open. (line 6)
* OpenCL C: OpenCL C. (line 6)
* OpenCL C Datatypes: OpenCL C Datatypes. (line 6)
* OpenCL C Expressions: OpenCL C Expressions.
(line 6)
* OpenCL C Operators: OpenCL C Operators. (line 6)
* OpenRISC 1000: OpenRISC 1000. (line 6)
* operate-and-get-next: Editing. (line 32)
* operating system information: Operating System Information.
(line 6)
* operating system information, process list: Process list. (line 6)
* optimized code, debugging: Optimized Code. (line 6)
* optimized code, wrong values of variables: Variables. (line 106)
* optimized out value in guile: Values From Inferior In Guile.
(line 102)
* optimized out value in Python: Values From Inferior.
(line 70)
* optimized out, in backtrace: Backtrace. (line 133)
* optional debugging messages: Debugging Output. (line 6)
* optional warnings: Messages/Warnings. (line 6)
* OS ABI: ABI. (line 11)
* OS information: OS Information. (line 6)
* out-of-line single-stepping: Maintenance Commands.
(line 112)
* outermost frame: Frames. (line 12)
* output formats: Output Formats. (line 6)
* output syntax of GDB/MI: GDB/MI Output Syntax.
(line 6)
* overlay area: How Overlays Work. (line 6)
* overlay example program: Overlay Sample Program.
(line 6)
* overlays: Overlays. (line 6)
* overlays, setting breakpoints in: Overlay Commands. (line 91)
* overloaded functions, calling: C Plus Plus Expressions.
(line 26)
* overloaded functions, overload resolution: Debugging C Plus Plus.
(line 59)
* overloading in C++: Debugging C Plus Plus.
(line 15)
* overloading, Ada: Overloading support for Ada.
(line 6)
* p packet: Packets. (line 271)
* P packet: Packets. (line 284)
* packet acknowledgment, for GDB remote: Packet Acknowledgment.
(line 6)
* packet size, remote protocol: General Query Packets.
(line 819)
* packets, notification: Notification Packets.
(line 6)
* packets, reporting on stdout: Debugging Output. (line 159)
* packets, tracepoint: Tracepoint Packets. (line 6)
* page size: Screen Size. (line 6)
* page tables display (MS-DOS): DJGPP Native. (line 55)
* pagination: Screen Size. (line 6)
* parameters in guile: Parameters In Guile.
(line 6)
* parameters in python: Parameters In Python.
(line 6)
* partial symbol dump: Symbols. (line 619)
* partial symbol tables, listing GDB's internal: Symbols. (line 645)
* Pascal: Summary. (line 35)
* Pascal objects, static members display: Print Settings. (line 570)
* Pascal support in GDB, limitations: Pascal. (line 6)
* pass signals to inferior, remote request: General Query Packets.
(line 440)
* patching binaries: Patching. (line 6)
* patching object files: Files. (line 26)
* pause current task (GNU Hurd): Hurd Native. (line 48)
* pause current thread (GNU Hurd): Hurd Native. (line 90)
* pauses in output: Screen Size. (line 6)
* pending breakpoints: Set Breaks. (line 245)
* physical address from linear address: DJGPP Native. (line 80)
* physname: Debugging Output. (line 41)
* pipe, target remote to: Connecting. (line 227)
* pipes: Starting. (line 64)
* pointer values, in file-i/o protocol: Pointer Values. (line 6)
* pointer, finding referent: Print Settings. (line 80)
* port rights, GNU Hurd: Hurd Native. (line 84)
* port sets, GNU Hurd: Hurd Native. (line 84)
* PowerPC architecture: PowerPC. (line 6)
* prefix for data files: Data Files. (line 6)
* prefix for executable and shared library file names: Files.
(line 386)
* premature return from system calls: Interrupted System Calls.
(line 6)
* preprocessor macro expansion, showing the results of: Macros.
(line 29)
* pretty print arrays: Print Settings. (line 115)
* pretty print C++ virtual function tables: Print Settings. (line 581)
* pretty-printer commands: Pretty-Printer Commands.
(line 6)
* print all frame argument values: Print Settings. (line 154)
* print an Objective-C object description: The Print Command with Objective-C.
(line 11)
* print array indexes: Print Settings. (line 125)
* print frame argument values for scalars only: Print Settings.
(line 154)
* print list of auto-loaded canned sequences of commands scripts: Auto-loading sequences.
(line 21)
* print list of auto-loaded Guile scripts: Guile Auto-loading.
(line 23)
* print list of auto-loaded Python scripts: Python Auto-loading.
(line 23)
* print messages on inferior start and exit: Inferiors and Programs.
(line 126)
* print messages on thread start and exit: Threads. (line 272)
* print messages when symbols are loaded: Symbols. (line 600)
* print settings: Print Settings. (line 6)
* print structures in indented form: Print Settings. (line 417)
* print/don't print memory addresses: Print Settings. (line 13)
* printing byte arrays: Output Formats. (line 60)
* printing data: Data. (line 6)
* printing frame argument values: Print Settings. (line 154)
* printing frame information: Print Settings. (line 314)
* printing nested structures: Print Settings. (line 362)
* printing strings: Output Formats. (line 60)
* probe static tracepoint marker: Create and Delete Tracepoints.
(line 75)
* probing markers, static tracepoints: Set Tracepoints. (line 28)
* process detailed status information: Process Information.
(line 88)
* process ID: Process Information.
(line 25)
* process info via /proc: Process Information.
(line 6)
* process list, QNX Neutrino: Process Information.
(line 126)
* process record and replay: Process Record and Replay.
(line 6)
* process status register: Registers. (line 31)
* processes, multiple: Forks. (line 6)
* procfs API calls: Process Information.
(line 105)
* profiling GDB: Maintenance Commands.
(line 438)
* program counter register: Registers. (line 31)
* program entry point: Backtrace. (line 155)
* programming in guile: Guile API. (line 6)
* programming in python: Python API. (line 6)
* progspaces in guile: Progspaces In Guile.
(line 6)
* progspaces in python: Progspaces In Python.
(line 6)
* prompt: Prompt. (line 6)
* protocol basics, file-i/o: Protocol Basics. (line 6)
* protocol, GDB remote serial: Overview. (line 14)
* protocol-specific representation of datatypes, in file-i/o protocol: Protocol-specific Representation of Datatypes.
(line 6)
* python api: Python API. (line 6)
* Python architectures: Architectures In Python.
(line 6)
* Python auto-loading: Python Auto-loading.
(line 6)
* python commands: Python Commands. (line 6)
* python commands <1>: Commands In Python. (line 6)
* python convenience functions: Functions In Python.
(line 6)
* python directory: Python. (line 12)
* python exceptions: Exception Handling. (line 6)
* python finish breakpoints: Finish Breakpoints in Python.
(line 6)
* python functions: Basic Python. (line 28)
* python module: Basic Python. (line 28)
* python modules: Python modules. (line 6)
* python pagination: Basic Python. (line 6)
* python parameters: Parameters In Python.
(line 6)
* python pretty printing api: Pretty Printing API.
(line 6)
* python scripting: Python. (line 6)
* python stdout: Basic Python. (line 6)
* Python, working with types: Types In Python. (line 6)
* python, working with values from inferior: Values From Inferior.
(line 6)
* q packet: Packets. (line 296)
* Q packet: Packets. (line 296)
* QAllow packet: General Query Packets.
(line 44)
* qAttached packet: General Query Packets.
(line 1381)
* qC packet: General Query Packets.
(line 55)
* QCatchSyscalls packet: General Query Packets.
(line 401)
* qCRC packet: General Query Packets.
(line 65)
* QDisableRandomization packet: General Query Packets.
(line 84)
* QEnvironmentHexEncoded packet: General Query Packets.
(line 144)
* QEnvironmentReset packet: General Query Packets.
(line 197)
* QEnvironmentUnset packet: General Query Packets.
(line 173)
* qfThreadInfo packet: General Query Packets.
(line 238)
* qGetTIBAddr packet: General Query Packets.
(line 303)
* qGetTLSAddr packet: General Query Packets.
(line 271)
* QNonStop packet: General Query Packets.
(line 379)
* qOffsets packet: General Query Packets.
(line 342)
* qP packet: General Query Packets.
(line 369)
* QPassSignals packet: General Query Packets.
(line 440)
* QProgramSignals packet: General Query Packets.
(line 469)
* qRcmd packet: General Query Packets.
(line 536)
* qSearch memory packet: General Query Packets.
(line 558)
* QSetWorkingDir packet: General Query Packets.
(line 219)
* QStartNoAckMode packet: General Query Packets.
(line 575)
* QStartupWithShell packet: General Query Packets.
(line 114)
* qsThreadInfo packet: General Query Packets.
(line 238)
* qSupported packet: General Query Packets.
(line 589)
* qSymbol packet: General Query Packets.
(line 1033)
* qTBuffer packet: Tracepoint Packets. (line 393)
* QTBuffer size packet: Tracepoint Packets. (line 406)
* QTDisable packet: Tracepoint Packets. (line 209)
* QTDisconnected packet: Tracepoint Packets. (line 228)
* QTDP packet: Tracepoint Packets. (line 10)
* QTDPsrc packet: Tracepoint Packets. (line 90)
* QTDV packet: Tracepoint Packets. (line 121)
* QTEnable packet: Tracepoint Packets. (line 204)
* qTfP packet: Tracepoint Packets. (line 335)
* QTFrame packet: Tracepoint Packets. (line 133)
* qTfSTM packet: Tracepoint Packets. (line 352)
* qTfV packet: Tracepoint Packets. (line 343)
* QThreadEvents packet: General Query Packets.
(line 509)
* qThreadExtraInfo packet: General Query Packets.
(line 1076)
* QTinit packet: Tracepoint Packets. (line 214)
* qTMinFTPILen packet: Tracepoint Packets. (line 171)
* QTNotes packet: Tracepoint Packets. (line 411)
* qTP packet: Tracepoint Packets. (line 307)
* QTro packet: Tracepoint Packets. (line 217)
* QTSave packet: Tracepoint Packets. (line 387)
* qTsP packet: Tracepoint Packets. (line 336)
* qTsSTM packet: Tracepoint Packets. (line 352)
* QTStart packet: Tracepoint Packets. (line 195)
* qTStatus packet: Tracepoint Packets. (line 234)
* qTSTMat packet: Tracepoint Packets. (line 381)
* QTStop packet: Tracepoint Packets. (line 201)
* qTsV packet: Tracepoint Packets. (line 344)
* qTV packet: Tracepoint Packets. (line 318)
* qualified thread ID: Threads. (line 52)
* query attached, remote request: General Query Packets.
(line 1381)
* quotes in commands: Completion. (line 83)
* quoting Ada internal identifiers: Additions to Ada. (line 76)
* quoting names: Symbols. (line 14)
* qXfer packet: General Query Packets.
(line 1113)
* r packet: Packets. (line 300)
* R packet: Packets. (line 305)
* range checking: Type Checking. (line 45)
* range stepping: Continuing and Stepping.
(line 217)
* ranged breakpoint: PowerPC Embedded. (line 33)
* ranges of breakpoints: Breakpoints. (line 45)
* Ravenscar Profile: Ravenscar Profile. (line 6)
* raw printing: Output Formats. (line 76)
* read special object, remote request: General Query Packets.
(line 1113)
* read, file-i/o system call: read. (line 6)
* read-only sections: Files. (line 265)
* reading symbols from relocatable object files: Files. (line 146)
* reading symbols immediately: Files. (line 94)
* readline: Editing. (line 6)
* Readline application name: Editing. (line 29)
* receive rights, GNU Hurd: Hurd Native. (line 84)
* recent tracepoint number: Create and Delete Tracepoints.
(line 122)
* record aggregates (Ada): Omissions from Ada. (line 44)
* record mode: Process Record and Replay.
(line 19)
* record serial communications on file: Remote Configuration.
(line 64)
* recording a session script: Bug Reporting. (line 108)
* recording inferior's execution and replaying it: Process Record and Replay.
(line 6)
* recordings in python: Recordings In Python.
(line 6)
* redirection: Input/Output. (line 6)
* reference card: Formatting Documentation.
(line 6)
* reference declarations: C Plus Plus Expressions.
(line 50)
* register packet format, MIPS: MIPS Register packet Format.
(line 6)
* registers: Registers. (line 6)
* regular expression: Set Breaks. (line 90)
* reloading the overlay table: Overlay Commands. (line 52)
* relocatable object files, reading symbols from: Files. (line 146)
* remote async notification debugging info: Debugging Output.
(line 136)
* remote connection commands: Connecting. (line 120)
* remote connection without stubs: Server. (line 6)
* remote debugging: Remote Debugging. (line 6)
* remote debugging, connecting: Connecting. (line 6)
* remote debugging, detach and program exit: Connecting. (line 19)
* remote debugging, symbol files: Connecting. (line 90)
* remote debugging, types of connections: Connecting. (line 6)
* remote memory comparison: Memory. (line 142)
* remote packets, enabling and disabling: Remote Configuration.
(line 159)
* remote programs, interrupting: Connecting. (line 239)
* remote protocol debugging: Debugging Output. (line 159)
* remote protocol, binary data: Overview. (line 63)
* remote protocol, field separator: Overview. (line 55)
* remote query requests: General Query Packets.
(line 6)
* remote serial debugging summary: Debug Session. (line 6)
* remote serial debugging, overview: Remote Stub. (line 14)
* remote serial protocol: Overview. (line 14)
* remote serial stub: Stub Contents. (line 6)
* remote serial stub list: Remote Stub. (line 53)
* remote serial stub, initialization: Stub Contents. (line 10)
* remote serial stub, main routine: Stub Contents. (line 15)
* remote stub, example: Remote Stub. (line 6)
* remote stub, support routines: Bootstrapping. (line 6)
* remote target: Target Commands. (line 58)
* remote target, file transfer: File Transfer. (line 6)
* remote target, limit break- and watchpoints: Remote Configuration.
(line 79)
* remote target, limit watchpoints length: Remote Configuration.
(line 91)
* remote timeout: Remote Configuration.
(line 72)
* remove actions from a tracepoint: Tracepoint Actions. (line 21)
* remove duplicate history: Command History. (line 54)
* rename, file-i/o system call: rename. (line 6)
* Renesas: Remote Stub. (line 62)
* repeated array elements: Print Settings. (line 348)
* repeating command sequences: Command Syntax. (line 41)
* repeating commands: Command Syntax. (line 21)
* replay log events, remote reply: Stop Reply Packets. (line 70)
* replay mode: Process Record and Replay.
(line 10)
* reporting bugs in GDB: GDB Bugs. (line 6)
* reprint the last value: Data. (line 112)
* reprint the last value <1>: Compiling and Injecting Code.
(line 74)
* reset environment, remote request: General Query Packets.
(line 197)
* resources used by commands: Maintenance Commands.
(line 509)
* response time, MIPS debugging: MIPS. (line 10)
* restart: Checkpoint/Restart. (line 6)
* restore data from a file: Dump/Restore Files. (line 6)
* restrictions on Go expressions: Go. (line 35)
* result records in GDB/MI: GDB/MI Result Records.
(line 6)
* resume threads of multiple processes simultaneously: All-Stop Mode.
(line 54)
* resuming execution: Continuing and Stepping.
(line 6)
* returning from a function: Returning. (line 6)
* reverse execution: Reverse Execution. (line 6)
* rewind program state: Checkpoint/Restart. (line 6)
* run to first instruction: Starting. (line 114)
* run to main procedure: Starting. (line 81)
* run until specified location: Continuing and Stepping.
(line 124)
* running: Starting. (line 6)
* running programs backward: Reverse Execution. (line 6)
* s packet: Packets. (line 312)
* S packet: Packets. (line 321)
* S12Z support: S12Z. (line 6)
* save breakpoints to a file for future sessions: Save Breakpoints.
(line 9)
* save command history: Command History. (line 36)
* save GDB output to a file: Logging Output. (line 6)
* save tracepoints for future sessions: save tracepoints. (line 6)
* scheduler locking mode: All-Stop Mode. (line 37)
* scope: M2 Scope. (line 6)
* screen size: Screen Size. (line 6)
* scripting commands: Command Files. (line 6)
* scripting with guile: Guile. (line 6)
* scripting with python: Python. (line 6)
* search for a thread: Threads. (line 258)
* search path for libthread_db: Threads. (line 293)
* searching memory: Searching Memory. (line 6)
* searching memory, in remote debugging: General Query Packets.
(line 558)
* searching source files: Search. (line 6)
* section offsets, remote request: General Query Packets.
(line 342)
* segment descriptor tables: DJGPP Native. (line 24)
* select Ctrl-C, BREAK or BREAK-g: Remote Configuration.
(line 108)
* select trace snapshot: tfind. (line 6)
* selected frame: Stack. (line 19)
* selecting guile pretty-printers: Selecting Guile Pretty-Printers.
(line 6)
* selecting python pretty-printers: Selecting Pretty-Printers.
(line 6)
* self tests: Maintenance Commands.
(line 360)
* self tests <1>: Maintenance Commands.
(line 366)
* semaphores on static probe points: Static Probe Points.
(line 20)
* send command to remote monitor: Connecting. (line 272)
* send command to simulator: Embedded Processors.
(line 9)
* send interrupt-sequence on start: Remote Configuration.
(line 121)
* send rights, GNU Hurd: Hurd Native. (line 84)
* send the output of a gdb command to a shell command: Shell Commands.
(line 25)
* sending files to remote systems: File Transfer. (line 6)
* separate debug sections: MiniDebugInfo. (line 6)
* separate debugging information files: Separate Debug Files.
(line 6)
* sequence-id, for GDB remote: Overview. (line 30)
* serial connections, debugging: Debugging Output. (line 159)
* serial line, target remote: Connecting. (line 129)
* serial protocol, GDB remote: Overview. (line 14)
* server prefix: Server Prefix. (line 6)
* server, command prefix: Command History. (line 20)
* set ABI for MIPS: MIPS. (line 32)
* set breakpoints in many functions: Set Breaks. (line 90)
* set breakpoints on all functions: Set Breaks. (line 117)
* set environment variable, remote request: General Query Packets.
(line 144)
* set fast tracepoint: Create and Delete Tracepoints.
(line 50)
* set inferior controlling terminal: Input/Output. (line 44)
* set static tracepoint: Create and Delete Tracepoints.
(line 75)
* set tdesc filename: Retrieving Descriptions.
(line 18)
* set tracepoint: Create and Delete Tracepoints.
(line 6)
* set working directory, remote request: General Query Packets.
(line 219)
* setting variables: Assignment. (line 6)
* setting watchpoints: Set Watchpoints. (line 6)
* settings: Command Settings. (line 39)
* SH: Remote Stub. (line 62)
* sh-stub.c: Remote Stub. (line 62)
* shared libraries: Files. (line 287)
* shared library events, remote reply: Stop Reply Packets. (line 65)
* shell command, exit code: Convenience Vars. (line 187)
* shell command, exit signal: Convenience Vars. (line 187)
* shell escape: Shell Commands. (line 10)
* show all convenience functions: Convenience Funs. (line 228)
* show all user variables and functions: Convenience Vars. (line 37)
* show inferior's working directory: Working Directory. (line 27)
* show last commands: Command History. (line 95)
* show tdesc filename: Retrieving Descriptions.
(line 25)
* signals: Signals. (line 6)
* signals the inferior may see, remote request: General Query Packets.
(line 469)
* SIGQUIT signal, dump core of GDB: Maintenance Commands.
(line 169)
* SingleKey keymap name: TUI Single Key Mode.
(line 53)
* size of remote memory accesses: Packets. (line 247)
* size of screen: Screen Size. (line 6)
* skipping over files via glob-style patterns: Skipping Over Functions and Files.
(line 55)
* skipping over functions and files: Skipping Over Functions and Files.
(line 6)
* skipping over functions via regular expressions: Skipping Over Functions and Files.
(line 68)
* snapshot of a process: Checkpoint/Restart. (line 6)
* software watchpoints: Set Watchpoints. (line 31)
* source file and line of a symbol: Print Settings. (line 50)
* source line and its code address: Machine Code. (line 6)
* source location: Specify Location. (line 6)
* source path: Source Path. (line 6)
* Sparc: Remote Stub. (line 65)
* sparc-stub.c: Remote Stub. (line 65)
* Sparc64 support: Sparc64. (line 6)
* sparcl-stub.c: Remote Stub. (line 68)
* SparcLite: Remote Stub. (line 68)
* Special Fortran commands: Special Fortran Commands.
(line 6)
* specifying location: Specify Location. (line 6)
* SSE registers (x86): Registers. (line 76)
* stack frame: Frames. (line 6)
* stack on Alpha: MIPS. (line 6)
* stack on MIPS: MIPS. (line 6)
* stack pointer register: Registers. (line 31)
* stacking targets: Active Targets. (line 6)
* standard registers: Registers. (line 31)
* start a new independent interpreter: Interpreters. (line 52)
* start a new trace experiment: Starting and Stopping Trace Experiments.
(line 6)
* starting: Starting. (line 6)
* startup code, and backtrace: Backtrace. (line 155)
* startup with shell, remote request: General Query Packets.
(line 114)
* stat, file-i/o system call: stat/fstat. (line 6)
* static members of C++ objects: Print Settings. (line 559)
* static members of Pascal objects: Print Settings. (line 570)
* static probe point, DTrace: Static Probe Points.
(line 6)
* static probe point, SystemTap: Static Probe Points.
(line 6)
* static tracepoints: Set Tracepoints. (line 28)
* static tracepoints, in remote protocol: General Query Packets.
(line 961)
* static tracepoints, setting: Create and Delete Tracepoints.
(line 75)
* status of trace data collection: Starting and Stopping Trace Experiments.
(line 27)
* status output in GDB/MI: GDB/MI Output Syntax.
(line 94)
* stepping: Continuing and Stepping.
(line 6)
* stepping and signal handlers: Signals. (line 106)
* stepping into functions with no line info: Continuing and Stepping.
(line 92)
* stop a running trace experiment: Starting and Stopping Trace Experiments.
(line 16)
* stop on C++ exceptions: Set Catchpoints. (line 16)
* stop reply packets: Stop Reply Packets. (line 6)
* stopped threads: Thread Stops. (line 6)
* stream records in GDB/MI: GDB/MI Stream Records.
(line 6)
* string tracing, in remote protocol: General Query Packets.
(line 978)
* struct gdb_reader_funcs: Writing JIT Debug Info Readers.
(line 22)
* struct gdb_symbol_callbacks: Writing JIT Debug Info Readers.
(line 43)
* struct gdb_unwind_callbacks: Writing JIT Debug Info Readers.
(line 43)
* struct return convention: i386. (line 7)
* struct stat, in file-i/o protocol: struct stat. (line 6)
* struct timeval, in file-i/o protocol: struct timeval. (line 6)
* struct/union returned in registers: i386. (line 7)
* structure field name completion: Completion. (line 135)
* stub example, remote debugging: Remote Stub. (line 6)
* stupid questions: Messages/Warnings. (line 49)
* styling: Output Styling. (line 6)
* Super-H: Super-H. (line 6)
* supported GDB/MI features, list: GDB/MI Support Commands.
(line 57)
* supported packets, remote query: General Query Packets.
(line 589)
* switching threads: Threads. (line 6)
* switching threads automatically: All-Stop Mode. (line 28)
* symbol cache size: Symbols. (line 698)
* symbol cache, flushing: Symbols. (line 714)
* symbol cache, printing its contents: Symbols. (line 706)
* symbol cache, printing usage statistics: Symbols. (line 710)
* symbol decoding style, C++: Print Settings. (line 529)
* symbol dump: Symbols. (line 619)
* symbol file functions: Debugging Output. (line 205)
* symbol files, remote debugging: Connecting. (line 90)
* symbol from address: Symbols. (line 95)
* symbol lookup: Debugging Output. (line 198)
* symbol lookup, remote request: General Query Packets.
(line 1033)
* symbol names: Symbols. (line 14)
* symbol table: Files. (line 6)
* symbol table creation: Debugging Output. (line 210)
* symbol tables in guile: Symbol Tables In Guile.
(line 6)
* symbol tables in python: Symbol Tables In Python.
(line 6)
* symbol tables, listing GDB's internal: Symbols. (line 645)
* symbol, source file and line: Print Settings. (line 50)
* symbols in guile: Symbols In Guile. (line 6)
* symbols in python: Symbols In Python. (line 6)
* symbols, never read: Files. (line 101)
* symbols, reading from relocatable object files: Files. (line 146)
* symbols, reading immediately: Files. (line 94)
* Synopsys ARC: ARC. (line 6)
* syscall DSO: Files. (line 193)
* system calls and thread breakpoints: Interrupted System Calls.
(line 6)
* system root, alternate: Files. (line 386)
* system, file-i/o system call: system. (line 6)
* system-wide configuration scripts: System-wide Configuration Scripts.
(line 6)
* system-wide init file: System-wide configuration.
(line 6)
* t packet: Packets. (line 331)
* T packet: Packets. (line 336)
* T packet reply: Stop Reply Packets. (line 26)
* tail call frames, debugging: Tail Call Frames. (line 6)
* target architecture: Targets. (line 17)
* target byte order: Byte Order. (line 6)
* target character set: Character Sets. (line 6)
* target debugging info: Debugging Output. (line 217)
* target descriptions: Target Descriptions.
(line 6)
* target descriptions, AArch64 features: AArch64 Features. (line 6)
* target descriptions, ARC Features: ARC Features. (line 6)
* target descriptions, ARM features: ARM Features. (line 6)
* target descriptions, enum types: Enum Target Types. (line 6)
* target descriptions, i386 features: i386 Features. (line 6)
* target descriptions, inclusion: Target Description Format.
(line 53)
* target descriptions, M68K features: M68K Features. (line 6)
* target descriptions, MicroBlaze features: MicroBlaze Features.
(line 6)
* target descriptions, MIPS features: MIPS Features. (line 6)
* target descriptions, NDS32 features: NDS32 Features. (line 6)
* target descriptions, Nios II features: Nios II Features. (line 6)
* target descriptions, OpenRISC 1000 features: OpenRISC 1000 Features.
(line 6)
* target descriptions, PowerPC features: PowerPC Features. (line 6)
* target descriptions, predefined types: Predefined Target Types.
(line 6)
* target descriptions, RISC-V Features: RISC-V Features. (line 6)
* target descriptions, RX Features: RX Features. (line 6)
* target descriptions, S/390 features: S/390 and System z Features.
(line 6)
* target descriptions, sparc32 features: Sparc Features. (line 6)
* target descriptions, sparc64 features: Sparc Features. (line 6)
* target descriptions, standard features: Standard Target Features.
(line 6)
* target descriptions, System z features: S/390 and System z Features.
(line 6)
* target descriptions, TIC6x features: TIC6x Features. (line 6)
* target descriptions, TMS320C6x features: TIC6x Features. (line 6)
* target descriptions, XML format: Target Description Format.
(line 6)
* target memory comparison: Memory. (line 142)
* target output in GDB/MI: GDB/MI Output Syntax.
(line 110)
* target stack description: Maintenance Commands.
(line 341)
* target-assisted range stepping: Continuing and Stepping.
(line 217)
* task attributes (GNU Hurd): Hurd Native. (line 48)
* task breakpoints, in Ada: Ada Tasks. (line 135)
* task exception port, GNU Hurd: Hurd Native. (line 67)
* task suspend count: Hurd Native. (line 59)
* task switching with program using Ravenscar Profile: Ravenscar Profile.
(line 10)
* TCP port, target remote: Connecting. (line 166)
* temporarily change settings: Command Settings. (line 39)
* terminal: Input/Output. (line 6)
* Text User Interface: TUI. (line 6)
* thread attributes info, remote request: General Query Packets.
(line 1076)
* thread breakpoints: Thread-Specific Breakpoints.
(line 10)
* thread breakpoints and system calls: Interrupted System Calls.
(line 6)
* thread create event, remote reply: Stop Reply Packets. (line 152)
* thread create/exit events, remote request: General Query Packets.
(line 509)
* thread default settings, GNU Hurd: Hurd Native. (line 130)
* thread exit event, remote reply: Stop Reply Packets. (line 181)
* thread ID lists: Threads. (line 65)
* thread identifier (GDB): Threads. (line 47)
* thread identifier (system): Threads. (line 35)
* thread info (Solaris): Threads. (line 167)
* thread information, remote request: General Query Packets.
(line 369)
* thread list format: Thread List Format. (line 6)
* thread number, per inferior: Threads. (line 47)
* thread properties, GNU Hurd: Hurd Native. (line 90)
* thread suspend count, GNU Hurd: Hurd Native. (line 109)
* THREAD-ID, in remote protocol: Packets. (line 20)
* threads and watchpoints: Set Watchpoints. (line 179)
* threads in python: Threads In Python. (line 6)
* threads of execution: Threads. (line 6)
* threads, automatic switching: All-Stop Mode. (line 28)
* threads, continuing: Thread Stops. (line 6)
* threads, stopped: Thread Stops. (line 6)
* time of command execution: Maintenance Commands.
(line 559)
* timeout for commands: Maintenance Commands.
(line 610)
* timeout for serial communications: Remote Configuration.
(line 72)
* timeout, for remote target connection: Remote Configuration.
(line 147)
* timestamping debugging info: Debugging Output. (line 224)
* trace experiment, status of: Starting and Stopping Trace Experiments.
(line 27)
* trace file format: Trace File Format. (line 6)
* trace files: Trace Files. (line 6)
* trace state variable value, remote request: Tracepoint Packets.
(line 318)
* trace state variables: Trace State Variables.
(line 6)
* traceback: Backtrace. (line 6)
* traceframe info format: Traceframe Info Format.
(line 6)
* tracepoint actions: Tracepoint Actions. (line 6)
* tracepoint conditions: Tracepoint Conditions.
(line 6)
* tracepoint data, display: tdump. (line 6)
* tracepoint deletion: Create and Delete Tracepoints.
(line 125)
* tracepoint number: Create and Delete Tracepoints.
(line 122)
* tracepoint packets: Tracepoint Packets. (line 6)
* tracepoint pass count: Tracepoint Passcounts.
(line 6)
* tracepoint restrictions: Tracepoint Restrictions.
(line 6)
* tracepoint status, remote request: Tracepoint Packets. (line 307)
* tracepoint variables: Tracepoint Variables.
(line 6)
* tracepoints: Tracepoints. (line 6)
* tracepoints support in gdbserver: Server. (line 272)
* trailing underscore, in Fortran symbols: Fortran. (line 9)
* translating between character sets: Character Sets. (line 6)
* TUI: TUI. (line 6)
* TUI commands: TUI Commands. (line 6)
* TUI configuration variables: TUI Configuration. (line 6)
* TUI key bindings: TUI Keys. (line 6)
* TUI single key mode: TUI Single Key Mode.
(line 6)
* type casting memory: Expressions. (line 41)
* type chain of a data type: Maintenance Commands.
(line 353)
* type checking: Checks. (line 24)
* type conversions in C++: C Plus Plus Expressions.
(line 26)
* type printer: Type Printing API. (line 9)
* type printing API for Python: Type Printing API. (line 6)
* types in guile: Types In Guile. (line 6)
* types in Python: Types In Python. (line 6)
* UDP port, target remote: Connecting. (line 215)
* union field name completion: Completion. (line 135)
* unions in structures, printing: Print Settings. (line 469)
* Unix domain socket: Connecting. (line 140)
* unknown address, locating: Output Formats. (line 35)
* unknown type: Symbols. (line 363)
* unlink, file-i/o system call: unlink. (line 6)
* unlinked object files: Files. (line 26)
* unload symbols from shared libraries: Files. (line 348)
* unmap an overlay: Overlay Commands. (line 39)
* unmapped overlays: How Overlays Work. (line 6)
* unset environment variable, remote request: General Query Packets.
(line 173)
* unset tdesc filename: Retrieving Descriptions.
(line 21)
* unsupported languages: Unsupported Languages.
(line 6)
* unwind stack in called functions: Calling. (line 36)
* unwind stack in called functions with unhandled exceptions: Calling.
(line 47)
* unwinding frames in Python: Unwinding Frames in Python.
(line 6)
* use only software watchpoints: Set Watchpoints. (line 108)
* user registers: Maintenance Commands.
(line 312)
* user-defined command: Define. (line 6)
* user-defined macros: Macros. (line 59)
* user-defined variables: Convenience Vars. (line 6)
* value history: Value History. (line 6)
* values from inferior, in guile: Values From Inferior In Guile.
(line 6)
* values from inferior, with Python: Values From Inferior.
(line 6)
* variable name conflict: Variables. (line 36)
* variable object debugging info: Debugging Output. (line 231)
* variable objects in GDB/MI: GDB/MI Variable Objects.
(line 9)
* variable values, wrong: Variables. (line 106)
* variables, readline: Readline Init File Syntax.
(line 34)
* variables, setting: Assignment. (line 16)
* vAttach packet: Packets. (line 350)
* vCont packet: Packets. (line 368)
* vCont? packet: Packets. (line 435)
* vCtrlC packet: Packets. (line 445)
* vector unit: Vector Unit. (line 6)
* vector, auxiliary: OS Information. (line 9)
* verbose operation: Messages/Warnings. (line 6)
* verify remote memory image: Memory. (line 142)
* verify target memory image: Memory. (line 142)
* vFile packet: Packets. (line 459)
* vFlashDone packet: Packets. (line 498)
* vFlashErase packet: Packets. (line 463)
* vFlashWrite packet: Packets. (line 478)
* vfork events, remote reply: Stop Reply Packets. (line 116)
* vforkdone events, remote reply: Stop Reply Packets. (line 128)
* virtual functions (C++) display: Print Settings. (line 581)
* vKill packet: Packets. (line 505)
* vMustReplyEmpty packet: Packets. (line 517)
* volatile registers: Registers. (line 106)
* vRun packet: Packets. (line 529)
* vStopped packet: Packets. (line 544)
* VTBL display: Print Settings. (line 581)
* watchdog timer: Maintenance Commands.
(line 610)
* watchpoints: Breakpoints. (line 17)
* watchpoints and threads: Set Watchpoints. (line 179)
* where to look for shared libraries: Files. (line 381)
* wild pointer, interpreting: Print Settings. (line 80)
* Wind River Linux system-wide configuration script: System-wide Configuration Scripts.
(line 22)
* word completion: Completion. (line 6)
* working directory: Source Path. (line 40)
* working directory (of your program): Working Directory. (line 6)
* working language: Languages. (line 13)
* write data into object, remote request: General Query Packets.
(line 1338)
* write, file-i/o system call: write. (line 6)
* writing a frame filter: Writing a Frame Filter.
(line 6)
* writing a Guile pretty-printer: Writing a Guile Pretty-Printer.
(line 6)
* writing a pretty-printer: Writing a Pretty-Printer.
(line 6)
* writing convenience functions: Functions In Python.
(line 6)
* writing into corefiles: Patching. (line 6)
* writing into executables: Patching. (line 6)
* writing into executables <1>: Compiling and Injecting Code.
(line 6)
* writing JIT debug info readers: Writing JIT Debug Info Readers.
(line 6)
* writing xmethods in Python: Writing an Xmethod. (line 6)
* wrong values: Variables. (line 106)
* x command, default address: Machine Code. (line 34)
* X packet: Packets. (line 547)
* Xilinx MicroBlaze: MicroBlaze. (line 6)
* XInclude: Target Description Format.
(line 53)
* XMD, Xilinx Microprocessor Debugger: MicroBlaze. (line 6)
* xmethod API: Xmethod API. (line 6)
* xmethods in Python: Xmethods In Python. (line 6)
* XML parser debugging: Debugging Output. (line 237)
* yanking text: Readline Killing Commands.
(line 6)
* z packet: Packets. (line 560)
* Z packets: Packets. (line 560)
* z0 packet: Packets. (line 575)
* Z0 packet: Packets. (line 575)
* z1 packet: Packets. (line 630)
* Z1 packet: Packets. (line 630)
* z2 packet: Packets. (line 651)
* Z2 packet: Packets. (line 651)
* z3 packet: Packets. (line 664)
* Z3 packet: Packets. (line 664)
* z4 packet: Packets. (line 677)
* Z4 packet: Packets. (line 677)