_TOUPPER(3P)               POSIX Programmer's Manual              _TOUPPER(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
       _toupper -- transliterate lowercase characters to uppercase

SYNOPSIS
       #include <ctype.h>

       int _toupper(int c);

DESCRIPTION
       The _toupper() macro shall be equivalent to toupper() except that the
       application shall ensure that the argument c is a lowercase letter.

RETURN VALUE
       Upon successful completion, _toupper() shall return the uppercase
       letter corresponding to the argument passed.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       Applications should use the toupper() function instead of the
       obsolescent _toupper() function.

RATIONALE
       None.

FUTURE DIRECTIONS
       The _toupper() function may be removed in a future version.

SEE ALSO
       islower(), toupper()

       The Base Definitions volume of POSIX.1-2017, Chapter 7, Locale,
       <ctype.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                         _TOUPPER(3P)