C语言整理之信号量

C语言之信号量

Semaphore1.c

#include <sys/ipc.h>

#include <sys/shm.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/shm.h>

#include <sys/ipc.h>

#include <sys/sem.h>

 

 

#define SHMKEY   1111

#define SHMSIZE  4096

#define SEMKEY   1111

 

union semun

{

int val;

struct semmid_ds *buf;

unsigned short *array;

struct seminfo *_buf;

 

};

 

int sem_p(int id)

{

int ret;

struct sembuf buf;

 

buf.sem_num = 0;

buf.sem_op = -1;

buf.sem_flg = SEM_UNDO;

 

ret = semop(id,&buf,1);

if(-1 == ret)

{

perror("semop");

return 1;

}

return 0;

}

 

int sem_v(int id)

{

 

int ret;

struct sembuf buf;

 

buf.sem_num = 0;

buf.sem_op = 1;

buf.sem_flg = SEM_UNDO;