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annotate docs/man3/SDL_SemTryWait.3 @ 3197:434ce3242e1c

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Alexei Tereschenko Why not to use hardware vertex processing instead of software one if it is available in D3D render driver? With hardware processing testsprite2 runs three times faster on all videocards which I could test.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 16 Jun 2009 14:34:15 +0000
parents 546f7c1eb755
children 1238da4a7112
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