freebsd/lib/libc/sys/getuid.2

.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)getuid.2	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd June 4, 1993
.Dt GETUID 2
.Os
.Sh NAME
.Nm getuid ,
.Nm geteuid
.Nd get user identification
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Fd #include <sys/types.h>
.Ft uid_t
.Fn getuid void
.Ft uid_t
.Fn geteuid void
.Sh DESCRIPTION
The
.Fn getuid
function returns the real user ID of the calling process.
The
.Fn geteuid
function
returns the effective user ID of the calling process.
.Pp
The real user ID is that of the user who has invoked the program.
As the effective user ID
gives the process additional permissions during
execution of
.Dq Em set-user-ID
mode processes,
.Fn getuid
is used to determine the real-user-id of the calling process.
.Sh ERRORS
The
.Fn getuid
and
.Fn geteuid
functions are always successful, and no return value is reserved to
indicate an error.
.Sh SEE ALSO
.Xr getgid 2 ,
.Xr issetugid 2 ,
.Xr setgid 2 ,
.Xr setreuid 2 ,
.Xr setuid 2
.Sh STANDARDS
The
.Fn geteuid
and
.Fn getuid
function calls are expected to conform to 
.St -p1003.1-90 .
.Sh HISTORY
A
.Fn getuid
and a
.Fn geteuid
function call appeared in
.At v7 .