WPARAM and LPARAM parameters

Question

When passing a value to a function that takes both a WPARAM and a LPARAM parameter, does it matter on which of them I pass it? Someone told me that if I use Windows x64 I sh

Answer 1

Yes, the order matters. WPARAM sent/posted in one side winds up WPARAM on the other end; likewise for LPARAM.

If you have your own custom messages you can use WPARAM and LPARAM for anything you want. (There may be some common conventions though.)