title: What does signal(SIGCHLD, SIG_DFL); mean?
body: <p>I am not handling <code>SIGCHLD</code> in my code. Still my process is removed immediately after termination. I want it to become zombie process.</p>
  <p>If I set <code>SIGCHLD</code> to <code>SIG_DFL</code> then, will it work? How do I set <code>SIGCHLD</code> to <code>SIG_DFL</code>?</p>
  <p>I want process to become zombie, so I can read the child status in parent after <code>waitpid</code>.</p>