NAME

sigsetmask — set current signal mask

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <signal.h>

int
sigsetmask(int mask);

sigmask(signum);

DESCRIPTION

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:

(void) sigsetmask(0);

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.