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.\" $FreeBSD$ 30.\" 31.Dd May 1, 2020 32.Dt GETGID 2 33.Os 34.Sh NAME 35.Nm getgid , 36.Nm getegid 37.Nd get group process identification 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft gid_t 43.Fn getgid void 44.Ft gid_t 45.Fn getegid void 46.Sh DESCRIPTION 47The 48.Fn getgid 49system call returns the real group ID of the calling process, 50.Fn getegid 51returns the effective group ID of the calling process. 52.Pp 53The real group ID is specified at login time. 54.Pp 55The real group ID is the group of the user who invoked the program. 56As the effective group ID gives the process additional permissions 57during the execution of 58.Dq Em set-group-ID 59mode processes, 60.Fn getgid 61is used to determine the real-user-id of the calling process. 62.Sh ERRORS 63The 64.Fn getgid 65and 66.Fn getegid 67system calls are always successful, and no return value is reserved to 68indicate an error. 69.Sh SEE ALSO 70.Xr getuid 2 , 71.Xr issetugid 2 , 72.Xr setgid 2 , 73.Xr setregid 2 74.Sh STANDARDS 75The 76.Fn getgid 77and 78.Fn getegid 79system calls are expected to conform to 80.St -p1003.1-90 . 81.Sh HISTORY 82The 83.Fn getgid 84function appeared in 85.At v4 . 86