op.h

自己编写的

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/sem.h>
#include <sys/shm.h>
#define	SIZE 1024
union semun {
	int val;
	struct semid_ds *buf;
	unsigned short *array;
};

int create_sem(key_t key)      /*   creat semaphore   */
{
	union semun mutex,empty,full;
	int semid;
	mutex.val = 1;
	empty.val = 10;
	full.val = 0;
	if((semid = semget(key, 3, 0666 | IPC_CREAT)) < 0) {
		printf("create semaphore error\n");
		exit(-1);
	}

	if((semctl(semid,0,SETVAL,mutex) < 0)|(semctl(semid,1,SETVAL,empty) < 0)|(semctl(semid,2,SETVAL,full) < 0)) {
		printf("set vale of semaphore error\n");
		exit(-1);
	}
	return semid;
}

int del_sem(int semid)
{
	union semun sem;
	sem.val = 0;
	if(semctl(semid,0,IPC_RMID,sem) < 0) {
		printf("delete semaphore error\n");
		exit(-1);
	}
	return 0;
}

int get_sem(key_t key)
{
	union semun sem;
	int semid;
	semid = semget(key,0,0);
	if(-1 == semid) {
		printf("get semaphore error\n");
		exit(-1);
	}
	return semid;
}


int p_mutex(int semid)
{
	struct sembuf sops;

	sops.sem_num = 0;
	sops.sem_op = -1;
	sops.sem_flg = SEM_UNDO;
	if(semop(semid, &sops, 1) == -1) {
		printf("p_mutex operation error\n");
		exit(-1);
	}
	return 0;
}
		
int p_empty(int semid)
{
	struct sembuf sops;
	sops.sem_num = 1;
	sops.sem_op = -1;
	sops.sem_flg = SEM_UNDO;
	if(semop(semid,&sops,1) == -1) {
		printf("p_empty operation error\n");
		exit(-1);
	}	
	return 0;
}

int p_full(int semid)
{
        struct sembuf sops;
        sops.sem_num = 2;
        sops.sem_op = -1;
        sops.sem_flg = SEM_UNDO;
        if(semop(semid,&sops,1) == -1) {
                printf("p_full operation error\n");
                exit(-1);
        }
        return 0;
}

int v_mutex(int semid)
{
        struct sembuf sops;
        sops.sem_num = 0;
        sops.sem_op = 1;
        sops.sem_flg = SEM_UNDO;
        if(semop(semid,&sops,1) == -1) {
                printf("v_mutex operation error\n");
                exit(-1);
        }
        return 0;
}

int v_empty(int semid)
{
        struct sembuf sops;
        sops.sem_num = 1;
        sops.sem_op = 1;
        sops.sem_flg = SEM_UNDO;
        if(semop(semid,&sops,1) == -1) {
                printf("v_empty operation error\n");
                exit(-1);
        }
        return 0;
}

int v_full(int semid)
{
        struct sembuf sops;
        sops.sem_num = 2;
        sops.sem_op = 1;
        sops.sem_flg = SEM_UNDO;
        if(semop(semid,&sops,1) == -1) {
                printf("v_full operation error\n");
                exit(-1);
        }
        return 0;
}