title: Writing to child process file descriptor
body: <p>I have a program "Sample" which takes input both from stdin and a non-standard file descriptor (3 or 4) as shown below</p>
  
  <pre><code>int pfds[2];
  pipe(pfds);    
  printf("%s","\nEnter input for stdin");
  read(0, pO, 5);    
  printf("\nEnter input for fds 3");
  read(pfds[0], pX, 5);
  
  printf("\nOutput stout");
  write(1, pO, strlen(pO));    
  printf("\nOutput fd 4");
  write(pfds[1], pX, strlen(pX));
  </code></pre>
  
  <p>Now i have another program "Operator" which executes the above program(Sample) in a child process using execv. Now what i want is to send input to "Sample" through the "Operator" .</p>