A/UX® Programmer's Reference Sections

sigprocmask(3P) sigprocmask(3P)
NAME
sigprocmask - examine and change blocked signals
SYNOPSIS
iinclude
int sigprocmask (how, set, oset)
int how;
sigset_t *set, oset;
DESCRIPTION
sigprocmask allows the calling process to examine or change
its signal mask. If the value of set is not NULL, it points to a set
of signals to be used to change the currently blocked set
The value of how indicates the manner in which the set is
changed. The permitted values for how are:
SIG BLOCK
SIG UNBLOCK
SIG SETMASK
The resulting set will be the union of the
current set and the signal set pointed to
by set.
The resulting set will be the intersection
of the current set and the complement of
the signal set pointed to by set.
The resulting set will be the signal set
pointed to by set.
If oset is not NULL, the previous mask is stored at the location
pointed to by set. If the value of set is NULL, the value of how is
ignored and the process's signal mask is unchanged. When set is
NULL, sigprocmask can be used to enquire about currently
blocked signals.
If there are any pending unblocked signals after the call to sigprocmask,
at least one of those signals will be delivered before
sigprocmask returns.
SIGKILL and SIGSTOP cannot be caught or ignored. SIGCONT
cannot be ignored. It is not possible to block these signals. This is
silently enforced.
RETURN VALUE
Upon successful completion, 0 is returned. Otherwise, -1 is re-
February, 1990
RevisionC
1