#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	int semid;
	int nsems = 1;
	int flags = 0666;
	struct sembuf buf;
	semid = semget(IPC_PRIVATE, nsems, flags);
	if(semid<0) {
		perror("semget");
		exit(EXIT_FAILURE);
	}
	printf("semáforo creado: %d\n", semid);
	buf.sem_num = 0;
	buf.sem_op  = 1;
	buf.sem_flg = IPC_NOWAIT;
	if((semop(semid, &buf, nsems)) < 0) {
		perror("semop");
		exit(EXIT_FAILURE);
	}
	system("ipcs -s");
	exit(EXIT_SUCCESS);
}