|SIGPROCMASK(2)||System Calls Manual||SIGPROCMASK(2)|
how, const sigset_t
sigprocmask() function examines and/or changes the current signal mask (those signals that are blocked from delivery). Signals are blocked if they are members of the current signal mask set.
If set is not null, the action of
sigprocmask() depends on the value of the parameter
how, which can be one of the following values:
If oset is not null, it is set to the previous value of the signal mask. When set is null, the value of how is insignificant and the mask remains unchanged, providing a way to examine the signal mask without modification.
The system quietly disallows
SIGSTOP to be blocked.
Only signals which are in the pending state will be blocked. Signals that are explicitly ignored or for which no handler has been installed and where the default action is to discard the signal are not held as pending and will be discarded regardless of the signal mask.
Blocked signals remain in the pending state until another call to
sigprocmask() removes the pending signal(s) from the
mask. If there are unblocked signals that are pending after the signal mask
is updated, at least one will be delivered before
sigprocmask() call will fail and the signal mask will be unchanged if one of the following occurs:
sigprocmask() function conforms to IEEE Std 1003.1-2008 (“POSIX.1”).
|May 29, 2017||OpenBSD-current|