| 1 | .TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" |
| 2 | .SH "NAME" |
| 3 | SDL_SemWait \- Lock a semaphore and suspend the thread if the semaphore value is zero\&. |
| 4 | .SH "SYNOPSIS" |
| 5 | .PP |
| 6 | \fB#include "SDL\&.h" |
| 7 | #include "SDL_thread\&.h" |
| 8 | .sp |
| 9 | \fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR); |
| 10 | .SH "DESCRIPTION" |
| 11 | .PP |
| 12 | \fBSDL_SemWait()\fP suspends the calling thread until either the semaphore pointed to by \fBsem\fR has a positive value, the call is interrupted by a signal or error\&. If the call is successful it will atomically decrement the semaphore value\&. |
| 13 | .PP |
| 14 | After \fBSDL_SemWait()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&. |
| 15 | .SH "RETURN VALUE" |
| 16 | .PP |
| 17 | Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&. |
| 18 | .SH "EXAMPLES" |
| 19 | .PP |
| 20 | .PP |
| 21 | .nf |
| 22 | \f(CWif (SDL_SemWait(my_sem) == -1) { |
| 23 | return WAIT_FAILED; |
| 24 | } |
| 25 | |
| 26 | \&.\&.\&. |
| 27 | |
| 28 | SDL_SemPost(my_sem);\fR |
| 29 | .fi |
| 30 | .PP |
| 31 | .SH "SEE ALSO" |
| 32 | .PP |
| 33 | \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR |
| 34 | .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00 |