c# - What are the definitions for LPARAM and WPARAM?

Question

I know I'm being lazy here and I should trawl the header files for myself, but what are the actual types for LPARAM and WPARAM parameters? Are they pointers, or four byte ints? I'm doing some C# interop code and want to be sure I get it working on x64 systems.

Answer 1

LPARAM is a typedef for LONG_PTR which is a long (signed 32-bit) on win32 and __int64 (signed 64-bit) on x86_64.

WPARAM is a typedef for UINT_PTR which is an unsigned int (unsigned 32-bit) on win32 and unsigned __int64 (unsigned 64-bit) on x86_64.

MSDN link