Multiple Raw Input Window Sinks

Question

I have a message-only window (ATL::CWindowImpl) that registers itself for raw input using the RIDEV_INPUTSINK flag, meaning it gets all input regardless of whether the window is the foreground window. This works great when there's only one instance of that window.

However, when I create more than 1 instance of my window, only one receives the WM_INPUT messages (I'm currently creating two, and only the second one to be created gets the messages).

RegisterRawInputDevices (using RIDEV_INPUTSINK | RIDEV_NOLEGACY) is succeeding during the creation of both windows. Also, the window not receiving raw input is still receiving other messages, so it's not a problem with the window itself...

If it's relevant, I'm using the VC11 beta, and windows are created and dispatching messages on different threads (using std::thread).

Is this an API limitation (i.e. you are limited to one input sink per process)? Or is there a way to get this working?

Thanks in advance.

EDIT:

Right now my current workaround is to just have one window and for it to pass on the input messages to the other windows, however this is a mess, and won't work in the case I want it to work in (where I have my app loading plugins which may want raw input, I don't want them to have to register with my app unless I really have to do it that way...).

Answer 1

From MSDN (here and here) the whole API for Raw Input talks always about application and not about window... which means that an application registering for raw input will be trated by the OS as one entitiy... which you indirectly proved by registering a second receiving winow - the first one just stopped receiving because the OS delivers raw input to the application (represented by exactly onw window as the sink).