getuid

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 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 syscall(2) for details regarding
       register mapping.

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

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                         GETUID(2)