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getuid
<html> <head> <title>getuid</title> <META NAME="KEYWORDS" CONTENT="getuid"> </head> <body BGCOLOR="#ffffff" LINK="#0000ff" VLINK="#0000ff" ALINK="#0000ff" TEXT="#000000"> <center> <h1><b>getuid</b></h1></center> <PRE> <STRONG><A HREF="/man2/GETUID">GETUID(2)</A></STRONG> Linux Programmer's Manual <STRONG><A HREF="/man2/GETUID">GETUID(2)</A></STRONG> NAME getuid, geteuid - get user identity SYNOPSIS #include <unistd.h> #include <sys/types.h> uid_t getuid(void); uid_t geteuid(void); DESCRIPTION getuid() returns the real user ID of the calling process. geteuid() returns the effective user ID of the calling process. ERRORS These functions are always successful. CONFORMING TO POSIX.1-2001, POSIX.1-2008, 4.3BSD. NOTES History In UNIX V6 the getuid() call returned (euid << 8) + uid. UNIX V7 in- troduced separate calls getuid() and geteuid(). The original Linux getuid() and geteuid() system calls supported only 16-bit user IDs. Subsequently, Linux 2.4 added getuid32() and ge- teuid32(), supporting 32-bit IDs. The glibc getuid() and geteuid() wrapper functions transparently deal with the variations across kernel versions. On Alpha, instead of a pair of getuid() and geteuid() system calls, a single getxuid() system call is provided, which returns a pair of real and effective UIDs. The glibc getuid() and geteuid() wrapper functions transparently deal with this. See <STRONG><A HREF="/man2/syscall">syscall(2)</A></STRONG> for details regarding register mapping. SEE ALSO <STRONG><A HREF="/man2/getresuid">getresuid(2)</A></STRONG>, <STRONG><A HREF="/man2/setreuid">setreuid(2)</A></STRONG>, <STRONG><A HREF="/man2/setuid">setuid(2)</A></STRONG>, <STRONG><A HREF="/man7/credentials">credentials(7)</A></STRONG> COLOPHON This page is part of release 5.05 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. Linux 2019-03-06 <STRONG><A HREF="/man2/GETUID">GETUID(2)</A></STRONG></PRE> <center> <h6>Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2025 <a href="http://www.he.net">Hurricane Electric</a>. All Rights Reserved.</h6></center> </body> </html>