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view docs/man3/SDL_SemWait.3 @ 4337:4eb6b4be1dbc SDL-1.2

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Fixed bug #728 I am using a headset on my monitor as primary sound output device. From time to time it happens that I switch off my monitor when I leave my computer and switch it on when I come back. When doing so while wesnoth is running I get no sound back when I switch on my monitor. There is probably good reason for that. Therefore I wanted to exit and restart wesnoth. Unfortunately, wesnoth always hangs in this situation. It looks like wesnoth can not be exited when the primary sound device vanished. I created a backtrace of this situation (please see attachment).
author Sam Lantinga <slouken@libsdl.org>
date Thu, 15 Oct 2009 02:52:11 +0000
parents 1238da4a7112
children
line wrap: on
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.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