1.\" Copyright (c) 1980, 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. 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.\" @(#)getuid.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/sys/getuid.2,v 1.7.2.4 2001/12/14 18:34:00 ru Exp $ 34.\" $DragonFly: src/lib/libc/sys/getuid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt GETUID 2 38.Os 39.Sh NAME 40.Nm getuid , 41.Nm geteuid 42.Nd get user identification 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.In unistd.h 47.In sys/types.h 48.Ft uid_t 49.Fn getuid void 50.Ft uid_t 51.Fn geteuid void 52.Sh DESCRIPTION 53The 54.Fn getuid 55function returns the real user ID of the calling process. 56The 57.Fn geteuid 58function 59returns the effective user ID of the calling process. 60.Pp 61The real user ID is that of the user who has invoked the program. 62As the effective user ID 63gives the process additional permissions during 64execution of 65.Dq Em set-user-ID 66mode processes, 67.Fn getuid 68is used to determine the real-user-id of the calling process. 69.Sh ERRORS 70The 71.Fn getuid 72and 73.Fn geteuid 74functions are always successful, and no return value is reserved to 75indicate an error. 76.Sh SEE ALSO 77.Xr getgid 2 , 78.Xr issetugid 2 , 79.Xr setgid 2 , 80.Xr setreuid 2 , 81.Xr setuid 2 82.Sh STANDARDS 83The 84.Fn geteuid 85and 86.Fn getuid 87function calls are expected to conform to 88.St -p1003.1-90 . 89.Sh HISTORY 90A 91.Fn getuid 92and a 93.Fn geteuid 94function call appeared in 95.At v7 . 96