title: What's the problem of pause() at all?
body: <p>According to <a href="http://www.gnu.org/s/hello/manual/libc/Pause-Problems.html#Pause-Problems" rel="nofollow noreferrer">this paragraph</a> ,the following has problem:</p>
  <pre><code> /* usr_interrupt is set by the signal handler.  */
   if (!usr_interrupt)
     pause ();
   
   /* Do work once the signal arrives.  */
   ...
  </code></pre>
  <p>And should use <a href="http://www.gnu.org/s/hello/manual/libc/Sigsuspend.html#Sigsuspend" rel="nofollow noreferrer"><code>sigsuspend</code></a> instead.</p>
  <p>But I still don't see what the problem is with <code>pause</code> and how <code>sigsuspend</code> solves it,</p>
  <p>anyone can explain in more details?</p>