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

int main() {

  struct timespec ts1, ts2;
  pid_t newpid;
  int fd1[2], fd2[2];

  char m0[] = "\n about to fork ..\n";
  char m1[] = "message from parent to child\n";
  char m2[] = "message from child to parent\n";
  char m3[] = "\n done ..\n";

  char rbuf1[256];
  char rbuf2[256];

  int cn1, cn2;

  if ((pipe(fd1)== -1)) printf(" error \n");
  if ((pipe(fd2)== -1)) printf(" error \n");

  printf("fd1 %d %d fd2 %d %d \n", fd1[0], fd1[1], fd2[0], fd2[1]);

  if ((newpid = fork()) == -1) { printf("error \n"); return 0;}
  
  if (newpid > 0) {
  
    close(fd1[1]); 
    close(fd2[0]);
    //    dup(fd2[1]); 
    //close(fd2[1]);
    write(6, m1, sizeof(m1));
    usleep(10000);
    cn1 = read(3, rbuf1, 256);
    write(1, rbuf1, cn1);
  }
  else {
    close (fd1[0]);
    close (fd2[1]);
    //dup (fd2[0]);
    //close (fd2[0]);
    write(4, m2, sizeof(m2));
    usleep(10000);
    cn2 = read(5, rbuf2, 256);
    write(1, rbuf2,cn2);
  }
  write(2,m3,sizeof(m3));

  return 0;
}