14 lines
254 B
C
14 lines
254 B
C
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#include <semaphore.h>
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#include "pthread_impl.h"
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int sem_trywait(sem_t *sem)
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{
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int val;
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while ((val=sem->__val[0]) > 0) {
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int new = val-1-(val==1 && sem->__val[1]);
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if (a_cas(sem->__val, val, new)==val) return 0;
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}
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errno = EAGAIN;
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return -1;
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}
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