bsd man page for sigsetmask

SIGSETMASK(2)							System Calls Manual						     SIGSETMASK(2)

NAME
       sigsetmask - set current signal mask

SYNOPSIS
       #include <signal.h>

       omask = sigsetmask(mask);
       long omask, mask;

       mask = sigmask(signum)
       long mask;
       int signum;

DESCRIPTION
       Sigsetmask  sets  the  current signal mask (those signals that are blocked from delivery).  Signals are blocked if the corresponding bit in
       mask is a 1; the macro sigmask is provided to construct the mask for a given signum.

       The system quietly disallows SIGKILL, SIGSTOP, or SIGCONT to be blocked.

RETURN VALUE
       The previous set of masked signals is returned.

SEE ALSO
       kill(2), sigvec(2), sigblock(2), sigpause(2)

4.2 Berkeley Distribution					   May 14, 1986 						     SIGSETMASK(2)