GETUID(2)                 (2019-03-06)                  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 pro-
          cess.

     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 sup-
          ported 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
          This page is part of release 5.10 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/.

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