shm.c

linux中设计简单的客户端和服务器端,是操作系统的上机题

#include<sys/types.h>
#include<sys/msg.h>
#include<sys/ipc.h>
#define SHMKEY  75                   /*定义共享区关键词*/
int shmid,i;
int *addr;

 CLIENT()
{	
	int i;	
	do{
	shmid=shmget(SHMKEY,100,0777); }
	while(shmid==-1);
	printf("client get shmid=%d\n",shmid);
	addr=shmat(shmid,0,0);                /*共享区起始地址为addr*/	
	for(i=9;i>=0;i--) 	
	{		
		while(*addr!= -1);	
		printf("(client)sent\n");                 /*打印（client）sent*/		
		*addr=i;                             /*把i赋给addr*/	
	}	
	exit(0);
}

 SERVER()
{ 	
	shmid=shmget(SHMKEY,100,0777|IPC_CREAT);  /*创建共享区*/	
	printf("server creat shmid=%d\n",shmid);
	addr=shmat(shmid,0,0);                         /*共享区起始地址为addr*/	
	do	
	{	
		*addr=-1;	
		while(*addr==-1);	
		printf("(server)received\n");               /*服务进程使用共享区*/	
	} 
	while(*addr);	
	shmctl(shmid,IPC_RMID,0);	
	exit(0);
	}

 main()
{	
	if(fork())SERVER();	
	else CLIENT();	
	wait(0);	
	wait(0);
}