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Colin Leroy 2011-01-26 04:24:20 PST

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the pthread implementation of SDL_SemWaitTimeout() uses busy waiting, while
pthread's sem_timedwait() does work. Attached are patches that make use of it
This commit is contained in:
Sam Lantinga 2011-01-27 00:34:12 -08:00
parent 71a8858bd9
commit b58487d8bb
2 changed files with 56 additions and 9 deletions
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39
src/thread/pthread/SDL_syssem.c
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@ -21,6 +21,7 @@
*/
#include "SDL_config.h"
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
@ -102,6 +103,8 @@ int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
{
int retval;
struct timeval now;
struct timespec ts_timeout;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
@ -116,16 +119,34 @@ SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
return SDL_SemWait(sem);
}
/* Ack! We have to busy wait... */
/* FIXME: Use sem_timedwait()? */
timeout += SDL_GetTicks();
/* Setup the timeout. sem_timedwait doesn't wait for
* a lapse of time, but until we reach a certain time.
* This time is now plus the timeout.
*/
gettimeofday(&now, NULL);
/* Add our timeout to current time */
now.tv_usec += (timeout % 1000) * 1000;
now.tv_sec += timeout / 1000;
/* Wrap the second if needed */
if ( now.tv_usec >= 1000000 ) {
now.tv_usec -= 1000000;
now.tv_sec ++;
}
/* Convert to timespec */
ts_timeout.tv_sec = now.tv_sec;
ts_timeout.tv_nsec = now.tv_usec * 1000;
/* Wait. */
do {
retval = SDL_SemTryWait(sem);
if (retval == 0) {
break;
}
SDL_Delay(1);
} while (SDL_GetTicks() < timeout);
retval = sem_timedwait(&sem->sem, &ts_timeout);
} while (retval < 0 && errno == EINTR);
if (retval < 0) {
SDL_SetError("sem_timedwait() failed");
}
return retval;
}