musl/include/semaphore.h

#ifndef _SEMAPHORE_H
#define _SEMAPHORE_H
#ifdef __cplusplus
extern "C" {
#endif

#define SEM_FAILED ((sem_t *)0)

typedef struct {
	long __val[4];
} sem_t;

int    sem_close(sem_t *);
int    sem_destroy(sem_t *);
int    sem_getvalue(sem_t *, int *);
int    sem_init(sem_t *, int, unsigned);
sem_t *sem_open(const char *, int, ...);
int    sem_post(sem_t *);
int    sem_timedwait(sem_t *, const struct timespec *);
int    sem_trywait(sem_t *);
int    sem_unlink(const char *);
int    sem_wait(sem_t *);

#ifdef __cplusplus
}
#endif
#endif