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 .