LB_GETTEXT

  This message copies a string from the listbox into a user-supplied buffer.
No length checking is done, so the user must insure that the buffer is
large enough to hold the string.

Parameters
  wParam is the 0-based index of the string to retrieve.
  lParam is a far pointer to the user-supplied buffer.

Returns
  TRUE if the string was copied, LB_ERR if there was an error.