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| .TH "UNW\\_GETCONTEXT" "3" "16 August 2007" "Programming Library " "Programming Library " |
| .SH NAME |
| unw_getcontext |
| \-\- get initial machine\-state |
| .PP |
| .SH SYNOPSIS |
| |
| .PP |
| #include <libunwind.h> |
| .br |
| .PP |
| int |
| unw_getcontext(unw_context_t *ucp); |
| .br |
| .PP |
| .SH DESCRIPTION |
| |
| .PP |
| The unw_getcontext() |
| routine initializes the context structure |
| pointed to by ucp |
| with the machine\-state of the call\-site. The |
| exact set of registers stored by unw_getcontext() |
| is |
| platform\-specific, but, in general, at least all preserved |
| (``callee\-saved\&'') and all frame\-related registers, such as the |
| stack\-pointer, will be stored. |
| .PP |
| This routine is normally implemented as a macro and applications |
| should not attempt to take its address. |
| .PP |
| .SH PLATFORM\-SPECIFIC NOTES |
| |
| .PP |
| On IA\-64, unw_context_t |
| has a layout that is compatible with |
| that of ucontext_t |
| and such structures can be initialized with |
| getcontext() |
| instead of unw_getcontext(). |
| However, the |
| reverse is \fInot\fP |
| true and it is \fInot\fP |
| safe to use structures |
| initialized by unw_getcontext() |
| in places where a structure |
| initialized by getcontext() |
| is expected. The reason for this |
| asymmetry is that unw_getcontext() |
| is optimized for maximum |
| performance and does not, for example, save the signal mask. |
| .PP |
| .SH RETURN VALUE |
| |
| .PP |
| On successful completion, unw_getcontext() |
| returns 0. |
| Otherwise, a value of \-1 is returned. |
| .PP |
| .SH THREAD AND SIGNAL SAFETY |
| |
| .PP |
| unw_getcontext() |
| is thread\-safe as well as safe to use |
| from a signal handler. |
| .PP |
| .SH SEE ALSO |
| |
| .PP |
| libunwind(3), |
| unw_init_local(3) |
| .PP |
| .SH AUTHOR |
| |
| .PP |
| David Mosberger\-Tang |
| .br |
| Email: \fBdmosberger@gmail.com\fP |
| .br |
| WWW: \fBhttp://www.nongnu.org/libunwind/\fP\&. |
| .\" NOTE: This file is generated, DO NOT EDIT. |
