Manpages - getuid.2
Table of Contents
NAME
getuid, geteuid - get user identity
SYNOPSIS
#include <unistd.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 and never modify errno.
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 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 *syscall*(2) for details regarding register mapping.
SEE ALSO
*getresuid*(2), *setreuid*(2), *setuid*(2), *credentials*(7)
COLOPHON
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