tune the preloads a bit
[sdl_omap.git] / docs / man3 / SDL_SemTryWait.3
... / ...
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1.TH "SDL_SemTryWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference"
2.SH "NAME"
3SDL_SemTryWait \- Attempt to lock a semaphore but don\&'t suspend the thread\&.
4.SH "SYNOPSIS"
5.PP
6\fB#include "SDL\&.h"
7#include "SDL_thread\&.h"
8.sp
9\fBint \fBSDL_SemTryWait\fP\fR(\fBSDL_sem *sem\fR);
10.SH "DESCRIPTION"
11.PP
12\fBSDL_SemTryWait\fP is a non-blocking varient of \fI\fBSDL_SemWait\fP\fR\&. If the value of the semaphore pointed to by \fBsem\fR is positive it will atomically decrement the semaphore value and return 0, otherwise it will return \fBSDL_MUTEX_TIMEOUT\fR instead of suspending the thread\&.
13.PP
14After \fBSDL_SemTryWait\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
17Returns \fB0\fR if the semaphore was successfully locked or either \fBSDL_MUTEX_TIMEOUT\fR or \fB-1\fR if the thread would have suspended or there was an error, respectivly\&.
18.PP
19If the semaphore was not successfully locked, the semaphore will be unchanged\&.
20.SH "EXAMPLES"
21.PP
22.PP
23.nf
24\f(CWres = SDL_SemTryWait(my_sem);
25
26if (res == SDL_MUTEX_TIMEOUT) {
27 return TRY_AGAIN;
28}
29if (res == -1) {
30 return WAIT_ERROR;
31}
32
33\&.\&.\&.
34
35SDL_SemPost(my_sem);\fR
36.fi
37.PP
38.SH "SEE ALSO"
39.PP
40\fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR
41.\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00