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#include <semaphore.h>
#include "pthread_impl.h"
int sem_post(sem_t *sem)
{
int val, waiters;
do {
val = sem->__val[0];
waiters = sem->__val[1];
if (val == SEM_VALUE_MAX) {
errno = EOVERFLOW;
return -1;
}
} while (a_cas(sem->__val, val, val+1+(val<0)) != val);
if (val<0 || waiters) __wake(sem->__val, 1, 0);
return 0;
}
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