1.\" $NetBSD: getgid.2,v 1.5 1995/02/27 12:32:53 cgd Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getgid.2 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt GETGID 2 38.Os BSD 4.2 39.Sh NAME 40.Nm getegid , 41.Nm getgid 42.Nd get group process identification 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Ft gid_t 46.Fo getegid 47.Fa void 48.Fc 49.Ft gid_t 50.Fo getgid 51.Fa void 52.Fc 53.Sh DESCRIPTION 54The 55.Fn getgid 56function returns the real group ID of the calling process, 57.Fn getegid 58returns the effective group ID of the calling process. 59.Pp 60The real group ID is specified at login time. 61.Pp 62The real group ID is the group of the user who invoked the program. 63As the effective group ID gives the process additional permissions 64during the execution of 65.Dq Em set-group-ID 66mode processes, 67.Fn getgid 68is used to determine the real-user-id of the calling process. 69.Sh ERRORS 70The 71.Fn getgid 72and 73.Fn getegid 74functions are always successful; 75no return value is reserved to indicate an error. 76.Sh LEGACY SYNOPSIS 77.Fd #include <sys/types.h> 78.Fd #include <unistd.h> 79.Pp 80The include file 81.In sys/types.h 82is necessary. 83.Sh SEE ALSO 84.Xr getuid 2 , 85.Xr setregid 2 , 86.Xr setgid 3 87.Sh STANDARDS 88.Fn getgid 89and 90.Fn getegid 91conform to 92.St -p1003.1-88 . 93