Visual c++ Converting String ^ to std::string (basic string)

private: string toString(String ^ s) {
    string n;
    using namespace Runtime::InteropServices;
    const char * chars = (const char * )(Marshal::StringToHGlobalAnsi(s)).ToPointer();
    n = chars;
    Marshal::FreeHGlobal(IntPtr((void * ) chars));
    return n;
}