title: Can I send signals to different threads
body: <p>Say I have a Thread A, which wants to send signals to Threads B, C and D. Can I do something like this.</p>
  
  <pre><code>SendSignalTo( ThreadB, SIGUSR1 );
  SendSignalTo( ThreadC, SIGUSR1 );
  SendSignalTo( ThreadD, SIGUSR1 );
  </code></pre>
  
  <p>With SIGUSR1 signal handler, defined differently for Thread B, C and D, like as follows.</p>
  
  <pre><code>void SIGUSR1_Handler_for_ThreadB(...){...}
  void SIGUSR1_Handler_for_ThreadC(...){...}
  void SIGUSR1_Handler_for_ThreadD(...){...}
  </code></pre>
  
  <p>And if not, what is the alternative.</p>