SIGSETMASK(3) BSD Library Functions Manual SIGSETMASK(3)NAMEsigsetmask — 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 deliv‐
ery if the corresponding bit in mask is a 1; the macro sigmask() is pro‐
vided 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:
(void) sigsetmask(0);
Which can be expressed via sigprocmask(2) as:
sigset_t eset;
sigemptyset(&eset);
(void) sigprocmask(SIG_SETMASK, &eset, NULL);
SEE ALSOkill(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 depre‐
cated.
BSD August 10, 2002 BSD
