getuid(3p) — Linux manual page

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

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(3p), geteuid(3p), getgid(3p), setegid(3p), seteuid(3p),
       setgid(3p), setregid(3p), setreuid(3p), setuid(3p)

       The Base Definitions volume of POSIX.1‐2017, sys_types.h(0p),
       unistd.h(0p)

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(3P)

Pages that refer to this page: unistd.h(0p), id(1p), getegid(3p), geteuid(3p), getgid(3p), getlogin(3p), getpwuid(3p), setegid(3p), seteuid(3p), setgid(3p), setregid(3p), setreuid(3p), setuid(3p)

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