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.\" 4. 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.\" @(#)getuid.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd June 4, 1993 32.Dt GETUID 2 33.Os 34.Sh NAME 35.Nm getuid , 36.Nm geteuid 37.Nd get user identification 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.In sys/types.h 43.Ft uid_t 44.Fn getuid void 45.Ft uid_t 46.Fn geteuid void 47.Sh DESCRIPTION 48The 49.Fn getuid 50system call returns the real user ID of the calling process. 51The 52.Fn geteuid 53system call 54returns the effective user ID of the calling process. 55.Pp 56The real user ID is that of the user who has invoked the program. 57As the effective user ID 58gives the process additional permissions during 59execution of 60.Dq Em set-user-ID 61mode processes, 62.Fn getuid 63is used to determine the real-user-id of the calling process. 64.Sh ERRORS 65The 66.Fn getuid 67and 68.Fn geteuid 69system calls are always successful, and no return value is reserved to 70indicate an error. 71.Sh SEE ALSO 72.Xr getgid 2 , 73.Xr issetugid 2 , 74.Xr setgid 2 , 75.Xr setreuid 2 , 76.Xr setuid 2 77.Sh STANDARDS 78The 79.Fn geteuid 80and 81.Fn getuid 82system calls are expected to conform to 83.St -p1003.1-90 . 84.Sh HISTORY 85The 86.Fn getuid 87and 88.Fn geteuid 89functions appeared in 90.At v7 . 91