1.\" Copyright (c) 1983, 1991, 1993 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.\" @(#)getgid.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/sys/getgid.2,v 1.8.2.4 2001/12/14 18:34:00 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/getgid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 31.\" 32.Dd June 4, 1993 33.Dt GETGID 2 34.Os 35.Sh NAME 36.Nm getgid , 37.Nm getegid 38.Nd get group process identification 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In sys/types.h 43.In unistd.h 44.Ft gid_t 45.Fn getgid void 46.Ft gid_t 47.Fn getegid void 48.Sh DESCRIPTION 49The 50.Fn getgid 51function returns the real group ID of the calling process, 52.Fn getegid 53returns the effective group ID of the calling process. 54.Pp 55The real group ID is specified at login time. 56.Pp 57The real group ID is the group of the user who invoked the program. 58As the effective group ID gives the process additional permissions 59during the execution of 60.Dq Em set-group-ID 61mode processes, 62.Fn getgid 63is used to determine the real-user-id of the calling process. 64.Sh ERRORS 65The 66.Fn getgid 67and 68.Fn getegid 69functions are always successful, and no return value is reserved to 70indicate an error. 71.Sh SEE ALSO 72.Xr getuid 2 , 73.Xr issetugid 2 , 74.Xr setgid 2 , 75.Xr setregid 2 76.Sh STANDARDS 77The 78.Fn getgid 79and 80.Fn getegid 81function calls are expected to conform to 82.St -p1003.1-90 . 83