SIGBLOCK(2)
NAME
sigblock − block signals
USAGE
sigblock(mask); int mask;
DESCRIPTION
Sigblock adds the signals specified in mask to the set of signals currently being blocked from delivery. Signal i is blocked if the ith bit in mask is a 1.
You cannot block SIGKILL, SIGSTOP, or SIGCONT.
RETURN VALUE
The previous set of masked signals is returned.