osx man page for sigsuspend

SIGSUSPEND(2)						      BSD System Calls Manual						     SIGSUSPEND(2)

NAME
     sigsuspend -- atomically release blocked signals and wait for interrupt

SYNOPSIS
     #include <signal.h>

     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, returning -1 with errno set to EINTR.

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

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

BSD
								   June 4, 1993 							       BSD