1.\" Copyright (c) 1980, 1991, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)setregid.2 8.2 (Berkeley) 4/16/94 29.\" $FreeBSD$ 30.\" 31.Dd April 16, 1994 32.Dt SETREGID 2 33.Os 34.Sh NAME 35.Nm setregid 36.Nd set real and effective group ID 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In unistd.h 41.Ft int 42.Fn setregid "gid_t rgid" "gid_t egid" 43.Sh DESCRIPTION 44The real and effective group ID's of the current process 45are set to the arguments. 46If the real group ID is changed, the saved group ID is changed to the 47new value of the effective group ID. 48.Pp 49Unprivileged users may change the real group 50ID to the effective group ID and vice-versa; only the super-user may 51make other changes. 52.Pp 53Supplying a value of -1 for either the real or effective 54group ID forces the system to substitute the current 55ID in place of the -1 argument. 56.Pp 57The 58.Fn setregid 59system call was intended to allow swapping 60the real and effective group IDs 61in set-group-ID programs to temporarily relinquish the set-group-ID value. 62This system call did not work correctly, 63and its purpose is now better served by the use of the 64.Xr setegid 2 65system call. 66.Pp 67When setting the real and effective group IDs to the same value, 68the standard 69.Fn setgid 70system call is preferred. 71.Sh RETURN VALUES 72.Rv -std setregid 73.Sh ERRORS 74.Bl -tag -width Er 75.It Bq Er EPERM 76The current process is not the super-user and a change 77other than changing the effective group-id to the real group-id 78was specified. 79.El 80.Sh SEE ALSO 81.Xr getgid 2 , 82.Xr issetugid 2 , 83.Xr setegid 2 , 84.Xr setgid 2 , 85.Xr setuid 2 86.Sh HISTORY 87The 88.Fn setregid 89system call appeared in 90.Bx 4.2 . 91