pipecommunication.c

给出一个应用双向管道进行不同进程间进行通信的实例。

#include <stdio.h>
#include <unistd.h>

int main(int argc,char *argv[])
{
	int f_des1[2];
	int f_des2[2];
	int pid;
	char msg[BUFSIZ];
	char p_msg[BUFSIZ];
	if(argc!=2){
		printf("Usage:%s message\n",argv[0]);
		return 1;
	}
	if(pipe(f_des1)==-1){
	perror("cannot creat the IPC pipe");
	return 1;
	}
	if(pipe(f_des2)==-1){
	perror("cannot create the IPC pipe");
	return 1;
	}
	pid=fork();
	if(pid==-1){
		perror("cannot create the new process");
		return 1;
	}
	else if(pid==0){
	close(f_des1[1]);
	close(f_des2[0]);
	if(read(f_des1[0],msg,BUFSIZ)==-1){
	perror("child process cannot read data from pipe");
	return 1;
	}
	else{
	printf("in child process,receive message:%s\n",msg);
	}
	if(write(f_des2[1],msg,strlen(msg))==-1){
	perror("child process cannot write dat to pipe");
	return 1;
	}
	else
	printf("in child process,send message back:%s\n",argv[1]);
	_exit(0);
	}
	else{
	close(f_des1[0]);
	close(f_des2[1]);
	if(write(f_des1[1],argv[1],strlen(argv[1]))==-1)
	{
		perror("parent process cannot write data to pipe");
		return 1;
	}
	else
		printf("in parent process,send message %s\n",argv[1]);

	if(read(f_des2[0],p_msg,BUFSIZ)==-1)
	{
		perror("parent process cannnot read the data from pipe");
		return 1;
	}else
		printf("in parent process,receive message:%s",p_msg);
	wait(NULL);
	_exit(0);
	}
	
	
}