view docs/man3/SDL_SemWait.3 @ 672:5955fa16d4b8

Date: Mon, 28 Jul 2003 18:30:50 +0300 From: "Mike Gorchak" Subject: New test for overlays While writting QNX Photon Overlay code I've found that the existent overlay test application is not enough, it performs too artificial tests - it always moves/resizes the overlay's viewport, but in the real life that happens very rare. So I decided to write new test (commonly base on testoverlay.c code) and called it testoverlay2 :) moose.dat - raw 8 bit paletted data of the small movie. (It was a moose.gif, also included in the attachment as reference, but not needed for this test, it is just for information). I cannot find, who created this .gif, so no credits this time :) But over inet I saw this gif zillion times, so I think we do not infringing somebody rights :)
author Sam Lantinga <slouken@libsdl.org>
date Fri, 08 Aug 2003 21:31:18 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SemWait\- Lock a semaphore and suspend the thread if the semaphore value is zero\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
#include "SDL_thread\&.h"
.sp
\fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR);
.SH "DESCRIPTION"
.PP
\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\&.
.PP
After \fBSDL_SemWait()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&.
.SH "RETURN VALUE"
.PP
Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWif (SDL_SemWait(my_sem) == -1) {
        return WAIT_FAILED;
}

\&.\&.\&.

SDL_SemPost(my_sem);\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\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
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00