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

  Converts a sequence of wide-character codes to a sequence of
  multibyte characters.

  Syntax:

       #include <stdlib.h>

       size_t wcstombs(char *s, const wchar_t *pwcs, size_t n);