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`iswalpha'--alphabetic wide-character test

     #include <wctype.h>
     int iswalpha(wint_t C);
`iswalpha' is a function which classifies wide-character values that
are alphabetic.
`iswalpha' returns non-zero if C is an alphabetic wide-character.
`iswalpha' is C99.
   No supporting OS subroutines are required.