How can my app find the sender of a windows message?

Question

I have an app which uses a keyboard hook procedure in a library. The wParam in the hook for one message is 255 which we think is \"(reserved / OEMClear)\". I\'d like to work

Answer 1

(I originally suggested using Spy++ or winspector, but they do not hook into the sending of messages. That doesn't even make sense! A window receives messages but they don't send them, a thread does that. I'll leave my suggestion about using a debugger.)

Sometimes debugging can help. Try downloading the windows PDB files and setting a breakpoint that hits only when one of these messages occur. Looking at the call stack at that point can often shed some light on why things are happening. Posted messages and messages send from other processes will foil this approach.