(PHP 5 >= 5.3.0)
pcntl_sigtimedwait — Waits for signals, with a timeout
$set
   [, array &$siginfo
   [, int $seconds = 0
   [, int $nanoseconds = 0
  ]]] )
   The pcntl_sigtimedwait() function operates in exactly
   the same way as pcntl_sigwaitinfo() except that it takes
   two additional parameters, seconds and
   nanoseconds, which enable an upper bound to be placed
   on the time for which the script is suspended.
  
setArray of signals to wait for.
siginfo
       The siginfo is set to an array containing
       informations about the signal. See
       pcntl_sigwaitinfo().
      
secondsTimeout in seconds.
nanosecondsTimeout in nanoseconds.
On success, pcntl_sigtimedwait() returns a signal number.