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.Dd May 1, 2020 29.Dt GETGID 2 30.Os 31.Sh NAME 32.Nm getgid , 33.Nm getegid 34.Nd get group process identification 35.Sh LIBRARY 36.Lb libc 37.Sh SYNOPSIS 38.In unistd.h 39.Ft gid_t 40.Fn getgid void 41.Ft gid_t 42.Fn getegid void 43.Sh DESCRIPTION 44The 45.Fn getgid 46system call returns the real group ID of the calling process, 47.Fn getegid 48returns the effective group ID of the calling process. 49.Pp 50The real group ID is specified at login time. 51.Pp 52The real group ID is the group of the user who invoked the program. 53As the effective group ID gives the process additional permissions 54during the execution of 55.Dq Em set-group-ID 56mode processes, 57.Fn getgid 58is used to determine the real-user-id of the calling process. 59.Sh ERRORS 60The 61.Fn getgid 62and 63.Fn getegid 64system calls are always successful, and no return value is reserved to 65indicate an error. 66.Sh SEE ALSO 67.Xr getuid 2 , 68.Xr issetugid 2 , 69.Xr setgid 2 , 70.Xr setregid 2 71.Sh STANDARDS 72The 73.Fn getgid 74and 75.Fn getegid 76system calls are expected to conform to 77.St -p1003.1-90 . 78.Sh HISTORY 79The 80.Fn getgid 81function appeared in 82.At v4 . 83