wm_copydata with postmessage

Question

on vista, sending wm_copydata message from dll to exe c++ mfc projects.

don't need a return value but sendmessage works and postmessage doesn't

using ChangeWindowMessageFilter(WM_COPYDATA,MSGFLT_ADD) in both apps.

anyone any ideas?

Answer 1

...its supposed to return an lResult (32 bit value) that says whether it honored the request, (!0) or not (0). PostMessage should never work for that, however. The buffer is temporary...PostMessage would not be able to gurarantee the content of the buffer had not changed. Its all spelled out here...
http://msdn.microsoft.com/en-us/library/ms649011(VS.85).aspx