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