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

  Compares no more than maxchar characters of two wide-character
  strings.  The function returns an integer that indicates if the
  strings are different and how they differ.

  Syntax:

       #include <wchar.h>

       int wcsncmp (const wchar_t *wstr_1, const wchar_t *wstr_2,
       size_t maxchar);