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.\"     @(#)sigsetops.3	8.1 (Berkeley) 6/4/93
.\"
.Dd October 29, 2019
.Dt SIGSETOPS 3
.Os
.Sh NAME
.Nm sigemptyset ,
.Nm sigfillset ,
.Nm sigaddset ,
.Nm sigandset ,
.Nm sigdelset ,
.Nm sigisemptyset ,
.Nm sigismember ,
.Nm sigorset
.Nd manipulate signal sets
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fn sigemptyset "sigset_t *set"
.Ft int
.Fn sigfillset "sigset_t *set"
.Ft int
.Fn sigaddset "sigset_t *set" "int signo"
.Ft int
.Fn sigandset "sigset_t *set" "const sigset_t *left" "const sigset_t *right"
.Ft int
.Fn sigdelset "sigset_t *set" "int signo"
.Ft int
.Fn sigisemptyset "const sigset_t *set"
.Ft int
.Fn sigismember "const sigset_t *set" "int signo"
.Ft int
.Fn sigorset "sigset_t *set" "const sigset_t *left" "const sigset_t *right"
.Sh DESCRIPTION
These functions manipulate signal sets stored in a
.Fa sigset_t .
Either
.Fn sigemptyset
or
.Fn sigfillset
must be called for every object of type
.Fa sigset_t
before any other use of the object.
.Pp
The
.Fn sigemptyset
function initializes a signal set to be empty.
.Pp
The
.Fn sigfillset
function initializes a signal set to contain all signals.
.Pp
The
.Fn sigaddset
function adds the specified signal
.Fa signo
to the signal set.
.Pp
The
.Fn sigandset
function sets the specified
.Fa set
to the logical AND of all signals from the
.Fa left
and
.Fa right
signal sets.
.Pp
The
.Fn sigdelset
function deletes the specified signal
.Fa signo
from the signal set.
.Pp
The
.Fn sigisemptyset
function returns whether the specified
.Fa set
is empty or not.
.Pp
The
.Fn sigismember
function returns whether a specified signal
.Fa signo
is contained in the signal set.
.Pp
The
.Fn sigorset
function sets the specified
.Fa set
to the logical OR of all signals from the
.Fa left
and
.Fa right
signal sets.
.Sh RETURN VALUES
The
.Fn sigisemptyset
function returns 1
if the set is empty, 0 otherwise.
.Pp
The
.Fn sigismember
function returns 1
if the signal is a member of the set,
0 otherwise.
.Pp
The other functions return 0 upon success.
A \-1 return value
indicates an error occurred and the global variable
.Va errno
is set to indicate the reason.
.Sh ERRORS
These functions could fail if one of the following occurs:
.Bl -tag -width Er
.It Bq Er EINVAL
.Fa signo
has an invalid value.
.El
.Sh SEE ALSO
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigpending 2 ,
.Xr sigprocmask 2 ,
.Xr sigsuspend 2
.Sh STANDARDS
The
.Fn sigandset ,
.Fn sigisemptyset ,
and
.Fn sigorset
functions are FreeBSD extensions, compatible with functions of the same name
provided by both musl libc and GNU libc.
.Pp
The rest of these functions are defined by
.St -p1003.1-88 .