int
     sigsuspend(const sigset_t *sigmask);

DESCRIPTION

     Sigsuspend() temporarily changes the blocked signal mask to the set to
     which sigmask points, and then waits for a signal to arrive; on return
     the previous set of masked signals is restored.  The signal mask set is
     usually empty to indicate that all signals are to be unblocked for the
     duration of the call.

     In normal usage, a signal is blocked using sigprocmask(2) to begin a
     critical section, variables modified on the occurrence of the signal are
     examined to determine that there is no work to be done, and the process
     pauses awaiting work by using sigsuspend() with the previous mask
     returned by sigprocmask.

RETURN VALUES

     The sigsuspend() function always terminates by being interrupted, return-
     ing -1 with errno set to EINTR.

SEE ALSO

     sigprocmask(2), sigaction(2), sigsetops(3)

STANDARDS

     The sigsupend function call conforms to IEEE Std 1003.1-1988
     (``POSIX.1'').

BSD                              June 4, 1993                              BSD