1.\" $OpenBSD: getuid.2,v 1.13 2008/08/04 07:08:23 jmc Exp $ 2.\" $NetBSD: getuid.2,v 1.6 1995/02/27 12:33:37 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)getuid.2 8.1 (Berkeley) 6/4/93 32.\" 33.Dd $Mdocdate: August 4 2008 $ 34.Dt GETUID 2 35.Os 36.Sh NAME 37.Nm getuid , 38.Nm geteuid 39.Nd get user identification 40.Sh SYNOPSIS 41.Fd #include <sys/types.h> 42.Fd #include <unistd.h> 43.Ft uid_t 44.Fn getuid void 45.Ft uid_t 46.Fn geteuid void 47.Sh DESCRIPTION 48The 49.Fn getuid 50function returns the real user ID of the calling process. 51The 52.Fn geteuid 53function returns the effective user ID of the calling process. 54.Pp 55The real user ID is that of the user who has invoked the program. 56As the effective user ID 57gives the process additional permissions during 58execution of 59.Dq Em set-user-ID 60mode processes, 61.Fn getuid 62is used to determine the real user ID of the calling process. 63.Sh ERRORS 64The 65.Fn getuid 66and 67.Fn geteuid 68functions are always successful, and no return value is reserved to 69indicate an error. 70.Sh SEE ALSO 71.Xr getgid 2 , 72.Xr getresuid 2 , 73.Xr setreuid 2 , 74.Xr setuid 2 75.Sh STANDARDS 76The 77.Fn getuid 78and 79.Fn geteuid 80functions conform to 81.St -p1003.1-88 . 82