RegSetValueEx shows only the first character of a record

In the following code, RegSetValueEx writes only the first letter of my string. I tried resizing to everything I can think of, and I only get the first row. Any help is appreciated.

LPCWSTR path = L"Test String";
size_t size = wclsen(path) * sizeof(wchar_t);

DWORD dwResult = RegSetValueEx(HKEY_LOCAL_MACHINE,
                            "SOFTWARE\\My App",
                            0,
                            REG_SZ,
                            (LPBYTE)path,
                            test);

I tried using path.size () * sizeof (wchar_t) and any number of other sizes that I could think of, but nothing seems to work. Any ideas?