lockpxsem.c

让你了解Unix进程间的通信是如何实现的

#include	"unpipc.h"

#define	LOCK_PATH	"pxsemlock"

sem_t	*locksem;
int		initflag;

void
my_lock(int fd)
{
	if (initflag == 0) {
		locksem = Sem_open(Px_ipc_name(LOCK_PATH), O_CREAT, FILE_MODE, 1);
		initflag = 1;
	}
	Sem_wait(locksem);
}

void
my_unlock(int fd)
{
	Sem_post(locksem);
}