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: src/lib/libc/sys/setregid.2,v 1.6.2.4 2001/12/14 18:34:01 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/setregid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 31.\" 32.Dd April 16, 1994 33.Dt SETREGID 2 34.Os 35.Sh NAME 36.Nm setregid 37.Nd set real and effective group ID 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft int 43.Fn setregid "gid_t rgid" "gid_t egid" 44.Sh DESCRIPTION 45The real and effective group ID's of the current process 46are set to the arguments. 47Unprivileged users may change the real group 48ID to the effective group ID and vice-versa; only the super-user may 49make other changes. 50.Pp 51Supplying a value of -1 for either the real or effective 52group ID forces the system to substitute the current 53ID in place of the -1 parameter. 54.Pp 55The 56.Fn setregid 57function was intended to allow swapping 58the real and effective group IDs 59in set-group-ID programs to temporarily relinquish the set-group-ID value. 60This function did not work correctly, 61and its purpose is now better served by the use of the 62.Fn setegid 63function (see 64.Xr setuid 2 ) . 65.Pp 66When setting the real and effective group IDs to the same value, 67the standard 68.Fn setgid 69function is preferred. 70.Sh RETURN VALUES 71.Rv -std setregid 72.Sh ERRORS 73.Bl -tag -width Er 74.It Bq Er EPERM 75The current process is not the super-user and a change 76other than changing the effective group-id to the real group-id 77was specified. 78.El 79.Sh SEE ALSO 80.Xr getgid 2 , 81.Xr issetugid 2 , 82.Xr setegid 2 , 83.Xr setgid 2 , 84.Xr setuid 2 85.Sh HISTORY 86The 87.Fn setregid 88system call appeared in 89.Bx 4.2 . 90