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 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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