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comparison docs/man3/SDL_SemTryWait.3 @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
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children 55f1f1b3e27d
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1 .TH "SDL_SemTryWait" "3" "Mon 12 Mar 2001, 01:04" "SDL" "SDL API Reference"
2 .SH "NAME"
3 SDL_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
14 After \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
17 Returns \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
19 If 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
26 if (res == SDL_MUTEX_TIMEOUT) {
27 return TRY_AGAIN;
28 }
29 if (res == -1) {
30 return WAIT_ERROR;
31 }
32
33 \&.\&.\&.
34
35 SDL_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, Mon 12 Mar 2001, 01:04