(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
pcntl_wstopsig — Returns the signal which caused the child to stop
   Returns the number of the signal which caused the child to stop.
   This function is only useful if
   pcntl_wifstopped() returned true.
  
   Returns the signal number.
   If the functionality is not supported by the OS, false is returned.
  
