geteuid(2) - Linux man page

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, 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.

See Also

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

Referenced By

awk(1), getlogin_r(3), mail-unlock(1), oping(8), pam_close_session(3), pam_open_session(3), ps(1), seteuid(2)