1#include <semaphore.h>
2#include <limits.h>
3#include "pthread_impl.h"
4
5int sem_trywait(sem_t *sem)
6{
7 int val;
8 while ((val=sem->__val[0]) & SEM_VALUE_MAX) {
9 if (a_cas(sem->__val, val, val-1)==val) return 0;
10 }
11 errno = EAGAIN;
12 return -1;
13}