GETUID(3)                  POSIX Programmer's Manual                 GETUID(3)



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

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 .



IEEE/The Open Group                  2017                            GETUID(3)
