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`iswctype'--extensible wide-character test

     #include <wctype.h>
     int iswctype(wint_t C, wctype_t DESC);
`iswctype' is a function which classifies wide-character values using
the wide-character test specified by DESC.
`iswctype' returns non-zero if and only if C matches the test specified
by DESC.  If DESC is unknown, zero is returned.
`iswctype' is C99.
   No supporting OS subroutines are required.