Retrieves the selected Unicode text. You can send this message explicitly or by using the Editor_GetSelTextW inline function.
wParam = (WPARAM) (UINT) nBufferSize;
lParam = (LPARAM) (LPWSTR) szBuffer;
Specifies the maximum number of characters in words to copy to the buffer, including the NULL character.
Pointer to the buffer that will receive the text.
If nBufferSize. is zero, the return value is the required size, in words, for a buffer that can receive the text. If nBufferSize is not zero, the return value is not used.