MDI Question

I have a MDI application with toolbars, statusbars, and other stuff
that is docked to main window. All these elements can be hidden
and showed at runtime. In MDI Child code, I need to know the real
area left for the MDI Child window.

ClientRect always returns (0, 0, ClientWidth, ClientHeight), but what if I
have a toolbar attached to top of main window? Then my client area would be
something like (WidthOfTheToolbar, 0, Width, Height).

Since these toolbars can be docked to another position and resized,
it is stupid and hard to always look for its position and width and
to check if its hidden or not.

So, I would like to know is there any efficient way to know the
real usable area left for MDI Child window (eg function that returns
something like (20, 20, 550, 400)).

Thanx, Vedran Rodic