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>
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11       uid_t getuid(void);
12       uid_t geteuid(void);
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DESCRIPTION

15       getuid() returns the real user ID of the calling process.
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17       geteuid() returns the effective user ID of the calling process.
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ERRORS

20       These functions are always successful and never modify errno.
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CONFORMING TO

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

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

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

46       This page is part of release 5.13 of the Linux  man-pages  project.   A
47       description  of  the project, information about reporting bugs, and the
48       latest    version    of    this    page,    can     be     found     at
49       https://www.kernel.org/doc/man-pages/.
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53Linux                             2021-03-22                         GETUID(2)
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