pipe

#include <unistd.h>

#include <stdio.h>

#include <stdlib.h>

int main()

{

    int fd[2];

    pipe(fd);//建立匿名管道

    if(fork())

    {

        /*fd[0] fd[1]*/

        close(fd[0]);//只负责写

        while(1)

        {

            write(fd[1],"HELLO",5);

            sleep(1);

        }

    }

    else

    {

        char buf[20];

        int r;

        /*fd[0] fd[1]*/

        close(fd[1]);//只负责读

        while(1)

        {

            r=read(fd[0],buf,20);

            buf[r]=0;

            printf("%s\n",buf);

        }

    }

}