[SDL] Making a GUI system in SDL

[L-28C]

Hello everyone!

My system works like this:

Control (base class)
  -- GUI (control container)
  -- Button (sample control)
  -- ...other controls

And the event system works like this (in this case we'll use mouse 
clicks): the main application calls the "OnClick()" method in the GUI 
class with the mouse pointer's position as a parameter. The GUI class 
then sees which control was clicked (based on the mouse's position), and 
calls the "OnClick()" method in that control (in this case we'll use a 
button). But here's the problem; how can this control (button) class let 
the main application know that it was clicked?

I tried to place a function pointer called "m_pfnOnClickEvent" and let 
the main application set a function to it when it creates the button... 
but C++ doesn't let you put member methods onto function pointers, and 
my program is 100% object-oriented.

Any ideas? Thanks!