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.\"     from: @(#)sigsetops.3	6.2 (Berkeley) 4/19/91
.\"	$Id: sigsetops.3,v 1.2 1993/07/30 08:39:09 mycroft Exp $
.\"
.Dd April 19, 1991
.Dt SIGSETOPS 3
.Os
.Sh NAME
.Nm sigsetops ,
.Nm sigemptyset ,
.Nm sigfillset ,
.Nm sigaddset ,
.Nm sigdelset ,
.Nm sigismember
.Nd manipulate signal masks
.Sh SYNOPSIS
.Fd #include <signal.h>
.Fn sigemptyset "sigset_t *set"
.Fn sigfillset "sigset_t *set"
.Fn sigaddset "sigset_t *set" "int signo"
.Fn sigdelset "sigset_t *set" "int signo"
.Fn sigismember "sigset_t *set" "int signo"
.Sh DESCRIPTION
These functions manipulate signal mask stored in a
.Fa sigset_t .
They are provided as macros, but actual functions are available
if their names are undefined (with #undef
.Em name ) .
.Pp
The
.Fn sigemptyset
function initializes a signal set to be empty.
The
.Fn sigfillset
function initializes a signal set to contain all of the known signals.
One of these routines must be used to initialize a signal set
before its use by the other functions.
.Pp
The
.Fn sigaddset
function adds a specified signal
.Fa signo
to a signal set.
The
.Fn sigdelset
function deletes a specified signal
.Fa signo
from a signal set.
.Pp
The
.Fn sigismember
function tests whether a specified signal
.Fa signo
is contained in a signal set.
.Sh RETURN VALUES
The
.Fn sigismember
function returnes 1
if the signal is a member of the set,
a 0 otherwise.
The other functions return 0 upon success.
A \-1 return value
indicates an error occurred and the global variable
.Va errno
is set to indicated the reason.
The current implementation does not detect any errors.
.Sh ERRORS
These functions could fail if one of the following occurs:
.Bl -tag -width [EINVAL]
.It Bq Er EINVAL
.Fa signo
has an invalid value.
.El
.Sh SEE ALSO
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigsetops 2 ,
.Xr sigsuspend 2
.Sh STANDARDS
The
These functions are defined by
.St -p1003.1-88 .
.Sh HISTORY
These functions are
.Ud .