操作系统 实验31 共享内存通信

1、共享内存通信

源程序：

shmmutexwrite.c

#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#define BUFFER_SIZE 10
#define sem_name "mysem"
int main()
{
struct Stu
{
char name[10];
int score;
};
int shmid;	
	sem_t*sem;								int score =60,i=1;					
	char buff[BUFFER_SIZE];
	key_t shmkey;							shmkey=ftok("shmmutexread.c",0);
	sem=sem_open(sem_name,O_CREAT,0644,1);

	if (sem == SEM_FAILED) {  
    	perror("sem_open");  
    	exit(EXIT_FAILURE);  
	}
	shmid=shmget(shmkey,1024,0666|IPC_CREAT);
	/*创建IPC键值为shmkey的共享内存，其大小为1024字节