PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

NAME

       getuid — get a real user ID

SYNOPSIS

       #include <unistd.h>

       uid_t getuid(void);

DESCRIPTION

       The  getuid() function shall return the real user ID of the calling process.  The getuid() function shall
       not modify errno.

RETURN VALUE

       The getuid() function shall always be successful and no return value is reserved to indicate the error.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

   Setting the Effective User ID to the Real User ID
       The following example sets the effective user ID of the calling process to the real user ID.

           #include <unistd.h>
           ...
           seteuid(getuid());

APPLICATION USAGE

       None.

RATIONALE

       In a conforming environment, getuid() will always succeed. It is possible for implementations to  provide
       an  extension where a process in a non-conforming environment will not be associated with a user or group
       ID. It is recommended that such implementations return (uid_t)-1  and  set  errno  to  indicate  such  an
       environment; doing so does not violate this standard, since such an environment is already an extension.

FUTURE DIRECTIONS

       None.

SEE ALSO

       getegid(), geteuid(), getgid(), setegid(), seteuid(), setgid(), setregid(), setreuid(), setuid()

       The Base Definitions volume of POSIX.1‐2017, <sys_types.h>, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE  and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .