double pipe

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

int main(int argc, char **argv){
    int p[2], p1[2], pid, n, m;
    char buf[10], buf1[10];
    pipe(p);
    pipe(p1);
    pid = fork();
    if(pid){
        close(p[0]);
        close(p1[1]);
        write(p[1],"ciao",5);
        do{
            m = read(p1[0],buf1,10);
        }while(m < 1);
        exit(1);
    }
    else{
        close(p[1]);
        close(p1[0]);
        wait(NULL);
        n = read(p[0],buf,10);
        write(STDOUT_FILENO,buf,n);
        write(p1[1],"ok",3);
        exit(1);
    }
    return 0;
}