bsd man page for sigblock

SIGBLOCK(2)							System Calls Manual						       SIGBLOCK(2)

NAME
       sigblock - block signals

SYNOPSIS
       #include <signal.h>

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

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

DESCRIPTION
       Sigblock causes the signals specified in mask to be added to the set of signals currently being 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.

       It is not possible to block SIGKILL, SIGSTOP, or SIGCONT;  this restriction is silently imposed by the system.

RETURN VALUE
       The previous set of masked signals is returned.

SEE ALSO
       kill(2), sigvec(2), sigsetmask(2)

4.2 Berkeley Distribution					   May 14, 1986 						       SIGBLOCK(2)