C++:将wchar_t*转换为BSTR？

BSTR wchar_t_to_BSTR(const wchar_t* wchar_str) {
    if (wchar_str == NULL) {
        return NULL;
    }
    int len = wcslen(wchar_str);
    BSTR bstr = SysAllocStringLen(NULL, len);
    if (bstr != NULL) {
        memcpy(bstr, wchar_str, len * sizeof(wchar_t));
    }
    return bstr;
}