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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)setregid.2 8.2 (Berkeley) 4/16/94 33.\" $FreeBSD: src/lib/libc/sys/setregid.2,v 1.6.2.4 2001/12/14 18:34:01 ru Exp $ 34.\" 35.Dd April 16, 1994 36.Dt SETREGID 2 37.Os 38.Sh NAME 39.Nm setregid 40.Nd set real and effective group ID 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft int 46.Fn setregid "gid_t rgid" "gid_t egid" 47.Sh DESCRIPTION 48The real and effective group ID's of the current process 49are set to the arguments. 50Unprivileged users may change the real group 51ID to the effective group ID and vice-versa; only the super-user may 52make other changes. 53.Pp 54Supplying a value of -1 for either the real or effective 55group ID forces the system to substitute the current 56ID in place of the -1 parameter. 57.Pp 58The 59.Fn setregid 60function was intended to allow swapping 61the real and effective group IDs 62in set-group-ID programs to temporarily relinquish the set-group-ID value. 63This function did not work correctly; 64its purpose is now better served by the use of the 65.Fn setegid 66function (see 67.Xr setuid 2 ) . 68.Pp 69When setting the real and effective group IDs to the same value, 70the standard 71.Fn setgid 72function is preferred. 73.Sh RETURN VALUES 74.Rv -std setregid 75.Sh ERRORS 76.Bl -tag -width Er 77.It Bq Er EPERM 78The current process is not the super-user and a change 79other than changing the effective group-id to the real group-id 80was specified. 81.El 82.Sh SEE ALSO 83.Xr getgid 2 , 84.Xr issetugid 2 , 85.Xr setegid 2 , 86.Xr setgid 2 , 87.Xr setuid 2 88.Sh HISTORY 89The 90.Fn setregid 91system call appeared in 92.Bx 4.2 . 93