#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<netdb.h>
#include<fcntl.h>
#include<string.h>
#include <errno.h>

int main()
{ pid_t  procid;  // used in fork
  int pfd[2];     // pipe descriptors
  char buffer0[256];
  char buffer1[256];
  char buffer2[256];
  int x,y,z;

  // create pipe
  x = pipe(pfd);  
  if (x != 0) { printf("pipe creation failed\n"); exit(1); }
  // parent will use pfd[0] to r/w, child use pfd[1]

  sprintf(buffer2,"%d",pfd[1]);  // make fd into string
   
  procid = fork();  // create child

  if (procid == 0)
    {
      x = execl("/usr/openwin/bin/xterm",
		"/usr/openwin/bin/xterm",
		"-e","./proc1",buffer2,NULL);
      printf("execl failed\n"); exit(1);
    }  // child

  // back to parent:

  //write some string to child:
  sprintf(buffer0,"proc0's string");
  write(pfd[0],buffer0,strlen(buffer0)+1);
  printf("proc0: sent string to proc1\n");
  //  read(pfd[1]  .. this will read your own data!
  read(pfd[0],buffer1,256);
  printf("proc0: received %s\n",buffer1);

  close(pfd[0]);
  close(pfd[1]);
  close(pfd[0]);
  exit(0);
}