equivalent to ref Message m in C++/winapi??

Hi All,

I have a C# project that contains this

protected override void WndProc(ref Message m)
        {
            switch (m.Msg)
            {

case WM_INITMENU:

//...

case WM_NCACTIVATE:

if (m.WParam == IntPtr.Zero){

m.Result = MESSAGE_HANDLED;

base.WndProc(ref m);

}

//...

}

}

I'd like to know how to convert this C# code to compatible C++/WINAPI.

thank you very much for helping.