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.\"     @(#)sigsetops.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/gen/sigsetops.3,v 1.6 2001/10/01 16:08:51 ru Exp $
.\"
.Dd June 4, 1993
.Dt SIGSETOPS 3
.Os
.Sh NAME
.Nm sigaddset ,
.Nm sigdelset ,
.Nm sigemptyset ,
.Nm sigfillset ,
.Nm sigismember
.Nd manipulate signal sets
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fo sigaddset
.Fa "sigset_t *set"
.Fa "int signo"
.Fc
.Ft int
.Fo sigdelset
.Fa "sigset_t *set"
.Fa "int signo"
.Fc
.Ft int
.Fo sigemptyset
.Fa "sigset_t *set"
.Fc
.Ft int
.Fo sigfillset
.Fa "sigset_t *set"
.Fc
.Ft int
.Fo sigismember
.Fa "const sigset_t *set"
.Fa "int signo"
.Fc
.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 sigdelset
function deletes the specified signal
.Fa signo
from the signal set.
.Pp
The
.Fn sigismember
function returns whether a specified signal
.Fa signo
is contained in the signal set.
.Pp
These functions
are provided as macros in the include file <signal.h>.
Actual functions are available
if their names are undefined (with #undef
.Em name ) .
.Sh RETURN VALUES
The
.Fn sigismember
function returns 1
if the signal is a member of the set,
0 otherwise.
The other functions return 0.
.Sh ERRORS
Currently, no errors are detected.
.Sh SEE ALSO
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigsuspend 2
.Sh STANDARDS
These functions are defined by
.St -p1003.1-88 .