Ascertains whether a given wide character is an uppercase letter
#include <wctype.h> int iswupper ( wint_t wc );
The iswupper( ) function is the wide-character version of the isupper( ) character classification function. It tests whether its character argument is a uppercase letter. If the character is a uppercase letter, isupper( ) returns a nonzero value (that is, TRue); if not, the function returns 0 (false).
Which characters are letters and which letters are uppercase both depend on the current locale setting for the category LC_CTYPE, which you can query or change using the setlocale( ) function. For some locale-specific characters, both iswupper( ) and iswlower( ) may return true, or both may return false even though iswalpha( ) returns true. However, iswupper( ) is mutually exclusive with iswcntrl( ), iswdigit( ), iswpunct( ), and iswspace( ) in all locales.
See the example for iswalpha( ) in this chapter.
iswlower( ), iswalpha( ); the corresponding function for byte characters, isupper( ); the extensible wide-character classification function, iswctype( ); iswalnum( ), iswblank( ), iswcntrl( ), iswdigit( ), iswgraph( ), iswprint( ), iswpunct( ), iswspace( ), iswxdigit( ), setlocale( ); the extensible wide-character classification function, iswctype( )