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

  Appends the wide character string wstr_2, including the terminating
  null character, to the end of wstr_1.

  Syntax:

       #include <wchar.h>

       wchar_t *wcscat (wchar_t *wstr_1, const wchar_t *wstr_2)