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annotate docs/man3/SDL_SemTryWait.3 @ 4347:38f22ed3a433 SDL-1.2

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Option to fix bug #851 For some people setting the period size works better (and is what SDL 1.2.13 did), but for most people it's the same or worse. You can use an environment variable to pick which one you want.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 17 Oct 2009 06:55:17 +0000
parents 1238da4a7112
children
rev   line source
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e5bc29de3f0a Updated from the SDL Documentation Project
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1 .TH "SDL_SemTryWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_SemTryWait \- Attempt to lock a semaphore but don\&'t suspend the thread\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 #include "SDL_thread\&.h"
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8 .sp
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9 \fBint \fBSDL_SemTryWait\fP\fR(\fBSDL_sem *sem\fR);
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10 .SH "DESCRIPTION"
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11 .PP
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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\&.
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13 .PP
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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\&.
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15 .SH "RETURN VALUE"
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16 .PP
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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\&.
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18 .PP
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19 If the semaphore was not successfully locked, the semaphore will be unchanged\&.
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20 .SH "EXAMPLES"
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21 .PP
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22 .PP
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23 .nf
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24 \f(CWres = SDL_SemTryWait(my_sem);
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25
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26 if (res == SDL_MUTEX_TIMEOUT) {
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27 return TRY_AGAIN;
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28 }
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29 if (res == -1) {
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30 return WAIT_ERROR;
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31 }
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32
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33 \&.\&.\&.
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34
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35 SDL_SemPost(my_sem);\fR
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36 .fi
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37 .PP
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38 .SH "SEE ALSO"
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39 .PP
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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
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41 .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00