I wrote a simple Hook DLL that communicates to its "creator process" with OpenFileMapping/MapViewOfFile during the DLL_PROCESS_ATTACH. After hook DLL has written some data to the Memory mapped file, it uses PostMessage no notify the "creator process" that new data is available in memory mapped file. When Posted Message arrives, creator just reads the input from file.
The communication is currently "one way" only, while I need two way communication.
My question is, what would be a best way to allow "creator process" easily respond true/false back to the Hook DLL (applications). I checked using SendMessage instead of PostMessage but it may be too slow.. I need to have a fast method.