GETUID(2) Linux Programmer's Manual GETUID(2)
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 introduced 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
geteuid32(), supporting 32-bit IDs. The glibc getuid() and geteuid() wrapper functions transparently deal with the variations across ker-
nel versions.
SEE ALSO
getresuid(2), setreuid(2), setuid(2), credentials(7)
COLOPHON
This page is part of release 4.15 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 2017-09-15 GETUID(2)
