Why do I think you need to multithread your app...?

In a single execution thread application, calling a function routes all processor time devoted to your function there. Even under Windows, your message loop is exactly that - a simple loop that handles incoming messages. You then try to respond to them as quickly as possible so as not to hold up the whole system. If you want to be able to call functions at will while responding to socket messages/connections/transmissions/whatever, you''re gonna need to place your socket code in a child thread.

I haven''t used CAsyncSocket (because I''m trying to write something reasonably portable here), but is it multithreaded? ie, does it somehow encapsulate a CThread object?

Good luck. I''ll let you know what I come up with.