What happens to WPARAM, LPARAM, and LRESULT when they travel between 32-bit and 64-bit windows?
The integral types , , and are 32 bits wide on 32-bit systems and 64 bits wide on 64-bit systems. What happens when a 32-bit process sends a message to a 64-bit window or vice versa? There's really only one choice when converting a 64-bit value to a 32-bit value: Truncation. When a 64-bit process sends a message to a 32-bit window, the 64-bit ...