VMS Help CC, Run-time functions, iswalnum  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Returns a nonzero integer if its wide-character argument is classed
  as alphabetic or as a digit in the program's current locale.
  Otherwise, it returns 0.

  Syntax:

       #include <wchar.h>

       int iswalnum (wint_t wc);