1 .TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 

     2 .SH "NAME"

     3 SDL_SemWait \- Lock a semaphore and suspend the thread if the semaphore value is zero\&.

     4 .SH "SYNOPSIS"

     5 .PP

     6 \fB#include "SDL\&.h"

     7 #include "SDL_thread\&.h"

     8 .sp

     9 \fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR);

    10 .SH "DESCRIPTION"

    11 .PP

    12 \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\&.

    13 .PP

    14 After \fBSDL_SemWait()\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 successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&.

    18 .SH "EXAMPLES"

    19 .PP

    20 .PP

    21 .nf

    22 \f(CWif (SDL_SemWait(my_sem) == -1) {

    23         return WAIT_FAILED;

    24 }

    25 

    26 \&.\&.\&.

    27 

    28 SDL_SemPost(my_sem);\fR

    29 .fi

    30 .PP

    31 .SH "SEE ALSO"

    32 .PP

    33 \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

    34 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00