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<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4> | |
<P><A HREF="index.html">Reference Index</A></P> | |
<P><A HREF="#toc">Table of Contents</A></P> | |
<H2><A HREF="#toc0" NAME="sect0">Name</A></H2> | |
<P>pthread_attr_init, pthread_attr_destroy, | |
pthread_attr_setdetachstate, pthread_attr_getdetachstate, | |
pthread_attr_setschedparam, pthread_attr_getschedparam, | |
pthread_attr_setschedpolicy, pthread_attr_getschedpolicy, | |
pthread_attr_setinheritsched, pthread_attr_getinheritsched, | |
pthread_attr_setscope, pthread_attr_getscope - thread creation | |
attributes | |
</P> | |
<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2> | |
<P><B>#include <pthread.h></B> | |
</P> | |
<P><B>int pthread_attr_init(pthread_attr_t *</B><I>attr</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_destroy(pthread_attr_t *</B><I>attr</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_setdetachstate(pthread_attr_t *</B><I>attr</I><B>, | |
int </B><I>detachstate</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_getdetachstate(const pthread_attr_t *</B><I>attr</I><B>, | |
int *</B><I>detachstate</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_setschedpolicy(pthread_attr_t *</B><I>attr</I><B>, | |
int </B><I>policy</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_getschedpolicy(const pthread_attr_t *</B><I>attr</I><B>, | |
int *</B><I>policy</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_setschedparam(pthread_attr_t *</B><I>attr</I><B>, | |
const struct sched_param *</B><I>param</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_getschedparam(const pthread_attr_t *</B><I>attr</I><B>, | |
struct sched_param *</B><I>param</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_setinheritsched(pthread_attr_t *</B><I>attr</I><B>, | |
int </B><I>inherit</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_getinheritsched(const pthread_attr_t *</B><I>attr</I><B>, | |
int *</B><I>inherit</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_setscope(pthread_attr_t *</B><I>attr</I><B>, | |
int </B><I>scope</I><B>);</B> | |
</P> | |
<P><B>int pthread_attr_getscope(const pthread_attr_t *</B><I>attr</I><B>, | |
int *</B><I>scope</I><B>);</B> | |
</P> | |
<H2><A HREF="#toc2" NAME="sect2">Description</A></H2> | |
<P>Setting attributes for threads is achieved by filling a thread | |
attribute object <I>attr</I> of type <B>pthread_attr_t</B>, then | |
passing it as second argument to <A HREF="pthread_create.html"><B>pthread_create</B>(3)</A> | |
. Passing <B>NULL</B> is equivalent to passing a thread attribute | |
object with all attributes set to their default values. | |
</P> | |
<P><B>pthread_attr_init</B> initializes the thread attribute object | |
<I>attr</I> and fills it with default values for the attributes. (The | |
default values are listed below for each attribute.) | |
</P> | |
<P>Each attribute <I>attrname</I> (see below for a list of all | |
attributes) can be individually set using the function | |
<B>pthread_attr_set</B><I>attrname</I> and retrieved using the | |
function <B>pthread_attr_get</B><I>attrname.</I> | |
</P> | |
<P><B>pthread_attr_destroy</B> destroys a thread attribute object, | |
which must not then be reused until it is reinitialized. | |
</P> | |
<P>Attribute objects are consulted only when creating a new thread. | |
The same attribute object can be used for creating several threads. | |
Modifying an attribute object after a call to <B>pthread_create</B> | |
does not change the attributes of the thread previously created. | |
</P> | |
<P>The following thread attributes are supported: | |
</P> | |
<H3><A HREF="#toc3" NAME="sect3">detachstate</A></H3> | |
<P>Control whether the thread is created in the joinable state (value | |
<B>PTHREAD_CREATE_JOINABLE</B>) or in the detached state ( | |
<B>PTHREAD_CREATE_DETACHED</B>). | |
</P> | |
<P>Default value: <B>PTHREAD_CREATE_JOINABLE</B>. | |
</P> | |
<P>In the joinable state, another thread can synchronize on the | |
thread termination and recover its termination code using | |
<A HREF="pthread_join.html"><B>pthread_join</B>(3)</A> . When a | |
joinable thread terminates, some of the thread resources are kept | |
allocated, and released only when another thread performs | |
<A HREF="pthread_join.html"><B>pthread_join</B>(3)</A> on that | |
thread. | |
</P> | |
<P>In the detached state, the thread's resources are released | |
immediately when it terminates. <A HREF="pthread_join.html"><B>pthread_join</B>(3)</A> | |
cannot be used to synchronize on the thread termination. | |
</P> | |
<P>A thread created in the joinable state can later be put in the | |
detached thread using <A HREF="pthread_detach.html"><B>pthread_detach</B>(3)</A> | |
. | |
</P> | |
<H3><A HREF="#toc4" NAME="sect4">schedpolicy</A></H3> | |
<P>Select the scheduling policy for the thread: one of <B>SCHED_OTHER</B> | |
(regular, non-real-time scheduling), <B>SCHED_RR</B> (real-time, | |
round-robin) or <B>SCHED_FIFO</B> (real-time, first-in first-out). | |
</P> | |
<P><B>Pthreads-w32</B> only supports <B>SCHED_OTHER</B> - attempting | |
to set one of the other policies will return an error ENOTSUP.</P> | |
<P>Default value: <B>SCHED_OTHER</B>. | |
</P> | |
<P><B>Pthreads-w32</B> only supports <B>SCHED_OTHER</B> - attempting | |
to set one of the other policies will return an error ENOTSUP.</P> | |
<P>The scheduling policy of a thread can be changed after creation | |
with <A HREF="pthread_setschedparam.html"><B>pthread_setschedparam</B>(3)</A> | |
. | |
</P> | |
<H3><A HREF="#toc5" NAME="sect5">schedparam</A></H3> | |
<P>Contain the scheduling parameters (essentially, the scheduling | |
priority) for the thread.</P> | |
<P><B>Pthreads-w32</B> supports the priority levels defined by the | |
Windows system it is running on. Under Windows, thread priorities are | |
relative to the process priority class, which must be set via the | |
Windows W32 API.</P> | |
<P>Default value: priority is 0 (Win32 level <B>THREAD_PRIORITY_NORMAL</B>). | |
</P> | |
<P>The scheduling priority of a thread can be changed after creation | |
with <A HREF="pthread_setschedparam.html"><B>pthread_setschedparam</B>(3)</A> | |
. | |
</P> | |
<H3><A HREF="#toc6" NAME="sect6">inheritsched</A></H3> | |
<P>Indicate whether the scheduling policy and scheduling parameters | |
for the newly created thread are determined by the values of the | |
<I>schedpolicy</I> and <I>schedparam</I> attributes (value | |
<B>PTHREAD_EXPLICIT_SCHED</B>) or are inherited from the parent | |
thread (value <B>PTHREAD_INHERIT_SCHED</B>). | |
</P> | |
<P>Default value: <B>PTHREAD_EXPLICIT_SCHED</B>. | |
</P> | |
<H3><A HREF="#toc7" NAME="sect7">scope</A></H3> | |
<P>Define the scheduling contention scope for the created thread. The | |
only value supported in the <B>Pthreads-w32</B> implementation is | |
<B>PTHREAD_SCOPE_SYSTEM</B>, meaning that the threads contend for CPU | |
time with all processes running on the machine. The other value | |
specified by the standard, <B>PTHREAD_SCOPE_PROCESS</B>, means that | |
scheduling contention occurs only between the threads of the running | |
process.</P> | |
<P><B>Pthreads-w32</B> only supports <B>PTHREAD_SCOPE_SYSTEM</B>.</P> | |
<P>Default value: <B>PTHREAD_SCOPE_SYSTEM</B>. | |
</P> | |
<H2><A HREF="#toc8" NAME="sect8">Return Value</A></H2> | |
<P>All functions return 0 on success and a non-zero error code on | |
error. On success, the <B>pthread_attr_get</B><I>attrname</I> | |
functions also store the current value of the attribute <I>attrname</I> | |
in the location pointed to by their second argument. | |
</P> | |
<H2><A HREF="#toc9" NAME="sect9">Errors</A></H2> | |
<P>The <B>pthread_attr_setdetachstate</B> function returns the | |
following error codes on error: | |
</P> | |
<DL> | |
<DL> | |
<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the specified <I>detachstate</I> is not one of | |
<B>PTHREAD_CREATE_JOINABLE</B> or <B>PTHREAD_CREATE_DETACHED</B>. | |
</DD></DL> | |
</DL> | |
<P> | |
The <B>pthread_attr_setschedparam</B> function returns the following | |
error codes on error: | |
</P> | |
<DL> | |
<DL> | |
<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the priority specified in <I>param</I> is outside the range of | |
allowed priorities for the scheduling policy currently in <I>attr</I> | |
(1 to 99 for <B>SCHED_FIFO</B> and <B>SCHED_RR</B>; 0 for | |
<B>SCHED_OTHER</B>). | |
</DD></DL> | |
</DL> | |
<P> | |
The <B>pthread_attr_setschedpolicy</B> function returns the following | |
error codes on error: | |
</P> | |
<DL> | |
<DL> | |
<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the specified <I>policy</I> is not one of <B>SCHED_OTHER</B>, | |
<B>SCHED_FIFO</B>, or <B>SCHED_RR</B>. | |
</DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
<B>ENOTSUP</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
<I>policy</I> is not <B>SCHED_OTHER</B>, the only value supported | |
by <B>Pthreads-w32</B>.</DD></DL> | |
</DL> | |
<P> | |
The <B>pthread_attr_setinheritsched</B> function returns the | |
following error codes on error: | |
</P> | |
<DL> | |
<DL> | |
<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the specified <I>inherit</I> is not one of <B>PTHREAD_INHERIT_SCHED</B> | |
or <B>PTHREAD_EXPLICIT_SCHED</B>. | |
</DD></DL> | |
</DL> | |
<P> | |
The <B>pthread_attr_setscope</B> function returns the following error | |
codes on error: | |
</P> | |
<DL> | |
<DL> | |
<DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"><B>EINVAL</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the specified <I>scope</I> is not one of <B>PTHREAD_SCOPE_SYSTEM</B> | |
or <B>PTHREAD_SCOPE_PROCESS</B>. | |
</DD><DT STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
<B>ENOTSUP</B> | |
</DT><DD STYLE="margin-right: 1cm; margin-bottom: 0.5cm"> | |
the specified <I>scope</I> is <B>PTHREAD_SCOPE_PROCESS</B> (not | |
supported by <B>Pthreads-w32</B>). | |
</DD></DL> | |
</DL> | |
<H2> | |
<A HREF="#toc10" NAME="sect10">Author</A></H2> | |
<P>Xavier Leroy <Xavier.Leroy@inria.fr> | |
</P> | |
<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P> | |
<H2><A HREF="#toc11" NAME="sect11">See Also</A></H2> | |
<P><A HREF="pthread_create.html"><B>pthread_create</B>(3)</A> , | |
<A HREF="pthread_join.html"><B>pthread_join</B>(3)</A> , | |
<A HREF="pthread_detach.html"><B>pthread_detach</B>(3)</A> , | |
<A HREF="pthread_setschedparam.html"><B>pthread_setschedparam</B>(3)</A> | |
. | |
</P> | |
<HR> | |
<P><A NAME="toc"></A><B>Table of Contents</B></P> | |
<UL> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A> | |
</P> | |
<UL> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">detachstate</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">schedpolicy</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">schedparam</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">inheritsched</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">scope</A> | |
</P> | |
</UL> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Return | |
Value</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">Errors</A> | |
</P> | |
<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect10" NAME="toc10">Author</A> | |
</P> | |
<LI><P><A HREF="#sect11" NAME="toc11">See Also</A> | |
</P> | |
</UL> | |
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