dual_pipe.c

此源码是著名的教材BeginningLinux Programming中文名字叫Linux程序设计书中的源代码

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

/*子进程读写管道的函数*/
void child_rw_pipe (int readfd, int writefd)
{
	char *message1 = "from child process!\n";
	write(writefd, message1,strlen(message1)+1);

	char message2[100];
	read (readfd,message2,100);
	printf("child process read from pipe:%s",message2);
}

/*父进程读写管道的函数*/
void parent_rw_pipe(int readfd,int writefd)
{
	char *message1 = "from parent process!\n";
	write(writefd, message1,strlen(message1)+1);

	char message2[100];
	read (readfd,message2,100);
	printf("parent process read from pipe:%s",message2);
} 

int main(void)
{
	int 	pipe1[2],pipe2[2];
	pid_t 	pid;
	int 	stat_val;

	printf("realize full-duplex communication:\n\n");
	if(pipe(pipe1))
	{
		printf("pipe1 failed!\n");
		exit(1);
	}
	if(pipe(pipe2))
	{
		printf("pipe2 failed!\n");
		exit(1);
	}

	pid = fork();
	switch(pid)
	{
		case -1:
			printf("fork error!\n");
			exit(1);
		case 0:
			/*子进程关闭pipe1的读端，关闭pipe2的写端*/
			close(pipe1[1]);
			close(pipe2[0]);
			child_rw_pipe(pipe1[0],pipe2[1]);
			exit(0);
		default:
			/*父进程关闭pipe2的写端，关闭pipe1的读端*/
			close(pipe1[0]);
			close(pipe2[1]);
	 		parent_rw_pipe(pipe2[0],pipe1[1]);
			wait(&stat_val);
			exit(0);
	}
}