---

---

---

GETUID

Section: Linux Programmer's Manual (2)
Updated: 2010-11-22
Index Return to Main Contents

---

 

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.

When a normal program is executed, the effective and real user ID of the process are set to the ID of the user executing the file. When a set ID program is executed the real user ID is set to the calling user and the effective user ID corresponds to the set ID bit on the file being executed.  

ERRORS

These functions are always successful.  

CONFORMING TO

POSIX.1-2001, 4.3BSD.  

NOTES

 

History

In UNIX V6 the getuid() call returned (euid << 8) + uid. UNIX V7 introduced separate calls getuid() and geteuid().  

NOTES

The original Linux getuid() and geteuid() system calls supported only 16-bit user IDs. Subsequently, Linux 2.4 added getuid32() and geteuid32(), supporting 32-bit IDs. The glibc getuid() and geteuid() wrapper functions transparently deal with the variations across kernel versions.  

SEE ALSO

getresuid(2), setreuid(2), setuid(2), credentials(7)  

COLOPHON

This page is part of release 3.35 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man-pages/.

---

 

Index

NAME

SYNOPSIS

DESCRIPTION

ERRORS

CONFORMING TO

NOTES

History

NOTES

SEE ALSO

COLOPHON

---

---

---