NAME
sigsetmask —
set current signal
mask
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <signal.h>
int
sigsetmask(
int
mask);
sigmask(
signum);
DESCRIPTION
This interface is
made obsolete by:
sigprocmask(2).
sigsetmask() sets the current signal mask. Signals are blocked
from delivery 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
or
SIGSTOP
to be blocked.
RETURN VALUES
The previous set of masked signals is returned.
EXAMPLES
The following example using
sigsetmask():
int omask;
omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
...
sigsetmask(omask & ~(sigmask(SIGINT) | sigmask(SIGHUP)));
Could be converted literally to:
sigset_t set, oset;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGHUP);
sigprocmask(SIG_BLOCK, &set, &oset);
...
sigdelset(&oset, SIGINT);
sigdelset(&oset, SIGHUP);
sigprocmask(SIG_SETMASK, &oset, NULL);
Another, clearer, alternative is:
sigset_t set;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGHUP);
sigprocmask(SIG_BLOCK, &set, NULL);
...
sigprocmask(SIG_UNBLOCK, &set, NULL);
To completely clear the signal mask using
sigsetmask() one can
do:
Which can be expressed via
sigprocmask(2) as:
sigset_t eset;
sigemptyset(&eset);
(void) sigprocmask(SIG_SETMASK, &eset, NULL);
SEE ALSO
kill(2),
sigaction(2),
sigprocmask(2),
sigsuspend(2),
sigblock(3),
sigsetops(3),
sigvec(3)
HISTORY
The
sigsetmask() function call appeared in
4.2BSD and has been deprecated.