3.c

简单的进程间通信

#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
	int pipe_fd[2];
	pid_t pid;
	char buf_r[100];
	char * p_wbuf;
	int r_num;
	memset(buf_r, 0, sizeof(buf_r));

	/*create pipe*/
	if(pipe(pipe_fd)<0)
	{
		printf("pipe create error!\n");
		return -1;
	}
	/*new son*/
	if((pid=fork())==0)
	{
		printf("\n");
		//close son's pipe's write function
		close(pipe_fd[1]);
		sleep(2);/*use sleep to wait and make sure the father's pipe's read function is closed */
		if((r_num=read(pipe_fd[0],buf_r,100))>0)
		{
			printf("Receive message from father: %s\n", buf_r);
		}
	close(pipe_fd[0]);
	exit(0);
	}
	else if(pid>0)
	{
		/*close father's pipe's read function*/
		close(pipe_fd[0]);
		if(write(pipe_fd[1],"Hello, son!",11)<0)
		{
			printf("Father write message error!\n");
		}else
			printf("Father sended out a message! The message is: Hello, son!\n");
		close(pipe_fd[1]);
		sleep(3);
		waitpid(pid,NULL,0);
		exit(0);
	}
}