.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     from: @(#)killpg.2	8.1 (Berkeley) 6/2/93
.\"	$NetBSD: killpg.3,v 1.16 2003/08/07 16:42:39 agc Exp $
.\"
.Dd June 2, 1993
.Dt KILLPG 3
.Os
.Sh NAME
.Nm killpg
.Nd send signal to a process group
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fn killpg "pid_t pgrp" "int sig"
.Sh DESCRIPTION
.Fn killpg
sends the signal
.Fa sig
to the process group
.Fa pgrp .
See
.Xr sigaction 2
for a list of signals.
If
.Fa pgrp
is 0,
.Fn killpg
sends the signal to the sending process's process group.
.Pp
The sending process and members of the process group must
have the same effective user ID, or
the sender must be the super-user.
As a single special case the continue signal SIGCONT may be sent
to any process that is a descendant of the current process.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, a value of \-1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn killpg
will fail and no signal will be sent if:
.Bl -tag -width Er
.It Bq Er EINVAL
.Fa sig
is not a valid signal number.
.It Bq Er ESRCH
No process can be found in the process group specified by
.Fa pgrp .
.It Bq Er ESRCH
The process group was given as 0
but the sending process does not have a process group.
.It Bq Er EPERM
The sending process is not the super-user and one or more
of the target processes has an effective user ID different from that
of the sending process.
.El
.Sh SEE ALSO
.Xr getpgrp 2 ,
.Xr kill 2 ,
.Xr sigaction 2
.Sh HISTORY
The
.Fn killpg
function call appeared in
.Bx 4.0 .