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mpv/osdep/semaphore.h

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#ifndef MP_SEMAPHORE_H_
#define MP_SEMAPHORE_H_
#include <sys/types.h>
#include <semaphore.h>
// OSX provides non-working empty stubs, so we emulate them.
// This should be AS-safe, but cancellation issues were ignored.
// sem_getvalue() is not provided.
// sem_post() won't always correctly return an error on overflow.
// Process-shared semantics are not provided.
#ifdef __APPLE__
#define MP_SEMAPHORE_EMULATION
#include <pthread.h>
#define MP_SEM_VALUE_MAX 4096
typedef struct {
int wakeup_pipe[2];
pthread_mutex_t lock;
// protected by lock
unsigned int count;
} mp_sem_t;
int mp_sem_init(mp_sem_t *sem, int pshared, unsigned int value);
int mp_sem_wait(mp_sem_t *sem);
int mp_sem_trywait(mp_sem_t *sem);
int mp_sem_timedwait(mp_sem_t *sem, const struct timespec *abs_timeout);
int mp_sem_post(mp_sem_t *sem);
int mp_sem_destroy(mp_sem_t *sem);
#undef sem_init
#undef sem_wait
#undef sem_trywait
#undef sem_timedwait
#undef sem_post
#undef sem_getvalue
#undef sem_destroy
#undef sem_getvalue
#undef sem_t
#undef SEM_VALUE_MAX
#define sem_init mp_sem_init
#define sem_wait mp_sem_wait
#define sem_trywait mp_sem_trywait
#define sem_timedwait mp_sem_timedwait
#define sem_post mp_sem_post
#define sem_destroy mp_sem_destroy
#define sem_t mp_sem_t
#define SEM_VALUE_MAX MP_SEM_VALUE_MAX
#define sem_getvalue (void)
#endif
#endif