23管道

#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <fcntl.h>

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>


#define ERR_EXIT(m) 	do 	{ 		perror(m); 		exit(EXIT_FAILURE); 	} while(0)


int main(int argc, char *argv[])
{
	int pipefd[2];
	if (pipe(pipefd) == -1)
		ERR_EXIT("pipe error");

	pid_t pid;
	pid = fork();
	if (pid == -1)
		ERR_EXIT("fork error");

	if (pid == 0)    //子进程
	{
		close(pipefd[0]);
		write(pipefd[1], "hello", 5);    //向管道内写
		close(pipefd[1]);
		exit(EXIT_SUCCESS);
	}

	close(pipefd[1]);
	char buf[10] = {0};
	read(pipefd[0], buf, 10);  //从管道内读
	printf("buf=%s\n", buf);
	
	return 0;

}