Interrupt WIN32 API functions help!!!

I'm writing a fractal generator that rasterizes the fractal through a certain amount of iterations, these iterations get more and more exact and take longer and longer to calculate... So this is what I want to do:

I want whenever an interrupt happens, like a keypress or mouse click anything that involves interaction from the user, for the program to STOP doing whatever function it is currently in, like calculating mathematics or printing to the screen, and idle as if the function was never called

E.g. When the program is in a loop calculating the mandelbrot set and you press a key I want that loop to stop and go to the user input function. I want this from any function within my program.

I looked into setting something up so whenever WndProc hears any messages that deal with keyboard input or mouse clicks then it will stop whatever loop it is in, but I just cant figure out how to do that! I would really like to stop the loops from within WndProc because it deals with all messages to the window that the fractal is being drawn upon.

If someone could please help me with this I'll be very very grateful!

Thank-you

If this is a console program:

A very simplistic way to do this would be to implement your own Control Handler. Check MSDN for SetConsoleCtrlHandler(). Have a global variable that indicates all is well. In your Control Handler, depending on what input you trapped, alter the variable to reflect that you want to stop. In your code to handle calculations, put an occasional check on a global variable, and if it has been altered, return prematurely. This means you could stop on something like a control + c, control + break, etc. etc.. The only downside is that such a stop is not immediate, although I suspect this is a decent solution for the effort put into implementing it.

If this is a Windows GUI program:

Then the same idea applies. Monitor a variable in your calculation code that is changed when you press a character sequence of some sort. The key presses should be picked up by your message loop or somewhere down the line. [Edit]You will need a separate thread for your calculation code, however, in this case.[/Edit]

Thats a great idea, and ive implemented it up to the thread part... I have no idea how to deal with threads in the WIN32 API. Is there any good source as to where I should look?

http://msdn.microsoft.com/en-ca/libr...41(VS.85).aspx