How can I share HWND between 32 and 64 bit applications in Win x64?

Question

MSDN tells me that handles to windows (HWND) can be shared between 32- and 64-bit applications, in Interprocess Communication (MSDN). However, in Win32 a HWND is 32 bits, w

Answer 1

Have a look in Microsoft Interface Definition Language (MIDL) Porting Guide, page 12 (http://msdn.microsoft.com/en-us/library/ms810720.aspx)

Here have a look ar USER and GDI handles are sign extended 32b values