SIGSETMASK(3) AerieBSD 1.0 Refernce Manual SIGSETMASK(3)

NAME

sigsetmask — set current signal mask

SYNOPSIS

#include <signal.h>

int sigsetmask(int mask); sigmask(int signum);

DESCRIPTION

.Bf -symbolic This interface is made obsoleted by: .Ef 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 utilizing 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.

AerieBSD 1.0 Reference Manual August 26 2008 SIGSETMASK(3)