Character Manipulation Function

int isupper(int c);

int iswupper(wint_t c);

int _ismbcupper(unsigned int c);

int _istupper(_TINT c);

Internationalization (I18n) Function Overview

The function isupper tests for an uppercase character, using the LC_CTYPE category setting of the current locale.

iswupper is the wide character equivalent of isupper, testing the wide character c.

On Windows platforms only, use _ismbcupper for the multibyte character equivalent. It returns nonzero if c is an uppercase character within the current multibyte character set.

_istupper is the Windows-only Generic version of the function; with the _MBCS or _UNICODE compiler flags determining its mapping to either _ismbcupper or iswupper.

I18n Issues

Use the appropriate version of the function as required for internationalization support, noting the following:

On ANSI platforms, there is no multibyte version of isupper. Instead, convert the character c to a wide character and call iswupper.

Prior to calling iswupper on ANSI platforms, ensure that the locale is set correctly, since the result of the test condition depends on the locale's LC_CTYPE category setting. On Windows platforms, the iswupper test is independent of locale.

The _ismbcupper function depends on the multibyte code page in effect. By default, the multibyte code page is set to the system-default ANSI code page obtained from the operating system at program startup. Use _getmbcp and _setmbcp to query or change the current multibyte code page, respectively.

Recommended Replacements*

ANSI UTF-8	convert to UTF-16 and call iswupper
ANSI UTF-16	iswupper
Microsoft Windows MBCS	_ismbcupper
Microsoft Windows Unicode	iswupper
Microsoft Windows Generic	_istupper

Character Manipulation Functions