7.25.2.1.11 The iswupper function
Synopsis
#include <wctype.h>
int iswupper(wint_t wc);
Description
The iswupper function tests for any wide character that corresponds to an uppercase letter or is one of a locale-specific set of wide characters for which none of iswcntrl, iswdigit, iswpunct, or iswspace is true.