SIGBLOCK(2) System Calls Manual SIGBLOCK(2)

sigblockblock signals

Standard C Library (libc, -lc)

#include <signal.h>

int
sigblock(int mask);

int
sigmask(signum);

This interface is made obsolete by sigprocmask(2).

() adds the signals specified in mask to the set of signals currently being blocked from delivery. Signals are blocked if the corresponding bit in mask is a 1; the macro () is provided to construct the mask for a given signum.

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

The previous set of masked signals is returned.

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

The sigblock() function call appeared in 4.2BSD and has been deprecated.

June 2, 1993 macOS 14.4