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

It's message-specific. You can use this list of system-defined message categories as reference. Select a group, then a message from the group to see what the message specifies you should pass as WPARAM/LPARAM.

Raymond Chen explains why we have two params.