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Command: sigblock | Section: 3 | Source: NetBSD | File: sigblock.3
SIGBLOCK(3) FreeBSD Library Functions Manual SIGBLOCK(3)
NAME
sigblock - block signals
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <signal.h>
int
sigblock(int mask);
int
sigmask(signum);
DESCRIPTION
This interface is made obsolete by: sigprocmask(2).
sigblock() 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 sigmask() 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.
RETURN VALUES
The previous set of masked signals is returned.
EXAMPLES
The following example using sigblock():
int omask;
omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
Becomes:
sigset_t set, oset;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGHUP);
sigprocmask(SIG_BLOCK, &set, &oset);
Another use of sigblock() is to get the current set of masked signals
without changing what is actually blocked. Instead of:
int set;
set = sigblock(0);
Use the following:
sigset_t set;
sigprocmask(SIG_BLOCK, NULL, &set);
SEE ALSO
kill(2), sigaction(2), sigprocmask(2), sigsetmask(3), sigsetops(3)
HISTORY
The sigblock() function call appeared in 4.2BSD and has been deprecated.
FreeBSD 14.1-RELEASE-p8 August 10, 2002 FreeBSD 14.1-RELEASE-p8