1GETUID(2)                  Linux Programmer's Manual                 GETUID(2)
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NAME

6       getuid, geteuid - get user identity
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SYNOPSIS

9       #include <unistd.h>
10       #include <sys/types.h>
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12       uid_t getuid(void);
13       uid_t geteuid(void);
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DESCRIPTION

16       getuid() returns the real user ID of the calling process.
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18       geteuid() returns the effective user ID of the calling process.
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ERRORS

21       These functions are always successful.
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CONFORMING TO

24       POSIX.1-2001, POSIX.1-2008, 4.3BSD.
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NOTES

27   History
28       In  UNIX V6  the getuid() call returned (euid << 8) + uid.  UNIX V7 in‐
29       troduced separate calls getuid() and geteuid().
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31       The original Linux getuid() and geteuid() system calls  supported  only
32       16-bit  user  IDs.   Subsequently,  Linux  2.4 added getuid32() and ge‐
33       teuid32(), supporting 32-bit IDs.  The  glibc  getuid()  and  geteuid()
34       wrapper  functions transparently deal with the variations across kernel
35       versions.
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37       On Alpha, instead of a pair of getuid() and geteuid() system  calls,  a
38       single  getxuid() system call is provided, which returns a pair of real
39       and effective UIDs.  The glibc getuid() and geteuid() wrapper functions
40       transparently  deal  with  this.   See syscall(2) for details regarding
41       register mapping.
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SEE ALSO

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

47       This page is part of release 5.10 of the Linux  man-pages  project.   A
48       description  of  the project, information about reporting bugs, and the
49       latest    version    of    this    page,    can     be     found     at
50       https://www.kernel.org/doc/man-pages/.
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54Linux                             2019-03-06                         GETUID(2)
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