signalcs2.c

操作系统的一些实验

#include<sys/types.h>
#include<sys/msg.h>
#include<sys/ipc.h>

#define SHMKEY 75

int shmid,i;
int *addr;

void CLIENT()
{
    int i;
    shmid=shmget(SHMKEY,1024,0777);
    addr=shmat(shmid,0,0);
    for(i=9; i>=0; i--)
    {
        while(*addr !=-1);
        printf("(client) sent\n");
        *addr=i;
    }
    exit(0);
}

void SERVER()
{
    shmid=shmget(SHMKEY,1024,0777|IPC_CREAT);
    addr=shmat(shmid,0,0);
    do{
	*addr=-1;
	while(*addr==-1);
        printf("(server) received\n");
    }while(*addr);
    shmctl(shmid,IPC_RMID,0);
    exit(0);
}

int main()
{
	while((i=fork())==-1);
	if(!i) SERVER();

	while((i=fork())==-1);
	if(!i) CLIENT();

	wait(0);
	wait(0);

	return 0;
}