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