Description

   The sigwaitinfo function behaves the same as the sigwait function
   if the info argument is NULL.

   If the info argument is non-NULL, the sigwaitinfo function
   behaves the same as sigwait, except that the selected signal
   number is stored in the si_signo member of the siginfo structure,
   and the cause of the signal is stored in the si_code member.
   If any value is queued to the selected signal, the first such
   queued value is dequeued and the value is stored in the si_value
   member of info. The system resource used to queue the signal is
   released and made available to queue other signals. If no value
   is queued, the content of the si_value member is undefined. If no
   further signals are queued for the selected signal, the pending
   indication for that signal is reset.

   See also sigtimedwait and sigwait.

   See the "Error and Signal Handling" chapter of the VSI C RTL
   Reference Manual for more information on signal handling.