1.\" Copyright (c) 1983, 1991 Regents of the University of California. 2.\" 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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)getgid.2 6.3 (Berkeley) 3/10/91 33.\" $Id: getgid.2,v 1.3 1993/10/04 18:31:22 jtc Exp $ 34.\" 35.Dd March 10, 1991 36.Dt GETGID 2 37.Os BSD 4.2 38.Sh NAME 39.Nm getgid , 40.Nm getegid 41.Nd get group process identification 42.Sh SYNOPSIS 43.Fd #include <sys/types.h> 44.Fd #include <unistd.h> 45.Ft gid_t 46.Fn getgid void 47.Ft gid_t 48.Fn getegid void 49.Sh DESCRIPTION 50The 51.Fn getgid 52function returns the real group ID of the calling process, 53.Fn getegid 54returns the effective group ID of the calling process. 55.Pp 56The real group ID is specified at login time. 57.Pp 58The real group ID is the group of the user who invoked the program. 59As the effective group ID gives the process additional permissions 60during the execution of 61.Dq Em set-group-ID 62mode processes, 63.Fn getgid 64is used to determine the real-user-id of the calling process. 65.Sh ERRORS 66The 67.Fn getgid 68and 69.Fn getegid 70functions are always successful, and no return value is reserved to 71indicate an error. 72.Sh SEE ALSO 73.Xr getuid 2 , 74.Xr setregid 2 , 75.Xr setgid 3 76.Sh STANDARDS 77.Fn Getgid 78and 79.Fn getegid 80conform to IEEE Std 1003.1-1988 81.Pq Dq Tn POSIX . 82