int
sigsetmask(
int mask
)
sigmask(
signum
)
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.
):
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);
)
function call appeared in
4.2BSD
and has been deprecated.