(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.
  
set
     Array of signals to wait for.
siginfo
     
       The siginfo is set to an array containing
       informations about the signal. See
        pcntl_sigwaitinfo().
      
seconds
     Timeout in seconds.
nanoseconds
     Timeout in nanoseconds.
On success, pcntl_sigtimedwait() returns a signal number.