sem_getvalue.c

来自「unix网络编程的源码」· C语言 代码 · 共 32 行

/* include sem_getvalue */
#include	"unpipc.h"
#include	"semaphore.h"

int
mysem_getvalue(mysem_t *sem, int *pvalue)
{
	int		n;

	if (sem->sem_magic != SEM_MAGIC) {
		errno = EINVAL;
		return(-1);
	}

	if ( (n = pthread_mutex_lock(&sem->sem_mutex)) != 0) {
		errno = n;
		return(-1);
	}
	*pvalue = sem->sem_count;
	pthread_mutex_unlock(&sem->sem_mutex);
	return(0);
}
/* end sem_getvalue */

void
Mysem_getvalue(mysem_t *sem, int *pvalue)
{
	if (mysem_getvalue(sem, pvalue) == -1)
		err_sys("mysem_getvalue error");
}