C++: convert strings to a usable string in MessageBox

s2ws.cpp

//used to convert strings to a usable string in MessageBox, example:
//std::wstring stemp = s2ws(executablePath);
//MessageBox(0, stemp.c_str(), L"", MB_OK);
//https://stackoverflow.com/a/27296
std::wstring s2ws(const std::string& s)
{
    int len;
    int slength = (int)s.length() + 1;
    len = MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, 0, 0); 
    wchar_t* buf = new wchar_t[len];
    MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, buf, len);
    std::wstring r(buf);
    delete[] buf;
    return r;
}