共享内存实现父子进程间通讯

//共享内存实现父子进程间通讯
//2013-10-30
//yang
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/ipc.h>
#include<sys/shm.h>
int main(void)
{
int shmid,pid=0,stop=3;
char *shm_p=NULL;
shmid = shmget(123456,2028,0600|IPC_CREAT);//创建共享内存
if(shmid == -1)
{
perror("shmget");
return 1;
}
shm_p = shmat(0600|IPC_CREAT,NULL,0);//对共享内存的映射实现父子进程可以调用内存
if(shm_p == NULL)
{
perror("shmat");
return 1;
}
pid = fork(); //创建进程
if(pid < 0)
{
printf("fork error");
}
if(pid == 0) //子进程
{
shm_p =(char *)malloc(strlen("hello...属于子进程")+1);

while(shm_p[0] != 'h')
{
memset(shm_p,'\0',strlen("hello...属于子进程")+1);
memcpy(shm_p,"hello...属于子进程",strlen("hello...属于子进程")+1);
}
puts(shm_p);
exit(stop);
}
else //父进程
{
wait(&stop);
//sleep(2);
shm_p =(char *)malloc(strlen("world...属于父进程")+1);
while(shm_p[0] != 'w')
{
memset(shm_p,'\0',strlen("world...属于父进程")+1);
strcat(shm_p,"world...属于父进程");
}
}
puts(shm_p);
free(shm_p);
shm_p = NULL;
}