title: How many kill signals this program needs to be terminqted
body: <p>I was given the program below in an exam and the question was how many kill signals must be sent to the process in order to terminate it. My answer was 3 signals, but the professor insisted on only 2 signals are needed to terminate the process? How is so?</p>
  
  <pre><code>static void action(int sig)
  {
      signal(SIGINT,SIG_DFL);
  }
  int main()
  {
      signal(SIGINT,SIG_IGN);
      signal(SIGUSR1,action);
      while(1)
          pause();
  }
  </code></pre>