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#include <semaphore.h>
#include <limits.h>
#include "pthread_impl.h"
int sem_post(sem_t *sem)
{
int val, new, waiters, priv = sem->__val[2];
do {
val = sem->__val[0];
waiters = sem->__val[1];
if ((val & SEM_VALUE_MAX) == SEM_VALUE_MAX) {
errno = EOVERFLOW;
return -1;
}
new = val + 1;
if (waiters <= 1)
new &= ~0x80000000;
} while (a_cas(sem->__val, val, new) != val);
if (val<0 || waiters) __wake(sem->__val, waiters>1 ? 1 : -1, priv);
return 0;
}
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