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SDL_syscond.c
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
slouken@devolution.com
*/
#ifdef SAVE_RCSID
static char rcsid =
"@(#) $Id$";
#endif
#ifdef linux
/* Look to see if glibc is available, and if so, what version */
#include <features.h>
#if (__GLIBC__ == 2) && (__GLIBC_MINOR__ == 0)
#warning Working around a bug in glibc 2.0 pthreads
#undef SDL_USE_PTHREADS
/* The bug is actually a problem where threads are suspended, but don't
wake up when the thread manager sends them a signal. This is a problem
with thread creation too, but it happens less often. :-/
We avoid this by using System V IPC for mutexes.
*/
#endif /* glibc 2.0 */
#endif /* linux */
#ifdef SDL_USE_PTHREADS
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include "SDL_error.h"
#include "SDL_thread.h"
#include "SDL_sysmutex_c.h"
#if defined(PTHREAD_NO_RECURSIVE_MUTEX) && !defined(__bsdi__)
#error You need to use the generic condition variable implementation
#endif
struct SDL_cond
{
pthread_cond_t cond;
};
/* Create a condition variable */
SDL_cond * SDL_CreateCond(void)
{
SDL_cond *cond;
cond = (SDL_cond *) malloc(sizeof(SDL_cond));
if ( cond ) {
if ( pthread_cond_init(&cond->cond, NULL) < 0 ) {
SDL_SetError("pthread_cond_init() failed");
free(cond);
cond = NULL;
}
}
return(cond);
}
/* Destroy a condition variable */
void SDL_DestroyCond(SDL_cond *cond)
{
if ( cond ) {
pthread_cond_destroy(&cond->cond);
free(cond);
}
}
/* Restart one of the threads that are waiting on the condition variable */
int SDL_CondSignal(SDL_cond *cond)
{
int retval;
if ( ! cond ) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
retval = 0;
if ( pthread_cond_signal(&cond->cond) != 0 ) {
SDL_SetError("pthread_cond_signal() failed");
retval = -1;
}
return retval;
}
/* Restart all threads that are waiting on the condition variable */
int SDL_CondBroadcast(SDL_cond *cond)
{
int retval;
if ( ! cond ) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
retval = 0;
if ( pthread_cond_broadcast(&cond->cond) != 0 ) {
SDL_SetError("pthread_cond_broadcast() failed");
retval = -1;
}
return retval;
}
int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)
{
int retval;
struct timeval delta;
struct timespec abstime;
if ( ! cond ) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
gettimeofday(&delta, NULL);
abstime.tv_sec = delta.tv_sec + (ms/1000);
abstime.tv_nsec = (delta.tv_usec+(ms%1000)) * 1000;
if ( abstime.tv_nsec > 1000000 ) {
abstime.tv_sec += 1;
abstime.tv_nsec -= 1000000;
}
tryagain:
retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
switch (retval) {
case EINTR:
goto tryagain;
break;
case ETIMEDOUT:
retval = SDL_MUTEX_TIMEDOUT;
break;
case 0:
break;
default:
SDL_SetError("pthread_cond_timedwait() failed");
retval = -1;
break;
}
return retval;
}
/* Wait on the condition variable, unlocking the provided mutex.
The mutex must be locked before entering this function!
*/
int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex)
{
int retval;
if ( ! cond ) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
retval = 0;
if ( pthread_cond_wait(&cond->cond, &mutex->id) != 0 ) {
SDL_SetError("pthread_cond_wait() failed");
retval = -1;
}
return retval;
}
#else /* Use semaphore implementation */
#include "generic/SDL_syscond.c"
#endif /* SDL_USE_PTHREADS */