Re: [Q] (Win32) On adding custom windows message to the NSRunLoop

[Fred Kiefer]

On 14.06.2012 09:29, Sungjin Chun wrote:
> I want to use 3rd party dll with GNUstep but struck with a problem;
> the dll needs a
> window handle(HANDLE) for its event processing, for example, if I want
> to receive
> realtime event notification, I have to write this kind of code;
>
> in WinMain function I have to use following windows message loop
>
> HANDLE hwnd = CreateWindow(.../* ordinary window creation */);
> while (GetMessage(...)) {
>    TranslateMessage(...);
>    DispatchMessage(...);
> }
>
> On other part, I have to register
> XXX_registerEventHandler(hwnd, WM_USER + MY_EVENT_ID);
>
> then, the dll emits windows message event WM_USER + MY_EVENT_ID so that
> I can handle the data in WndProc(which is lpfnWndProc for hwnd).
>
> Now my question is that I can get handle of a window from NSWindow>>nativeHandle
> method, but how can I register event handler(NSRunLoop, right?) for
> WM_USER + MY_EVENT_ID?
>
> Thanks in advance and sorry for my poor english.

Currently there is no direct way to do this properly with GNUstep. At 
the moment we ignore all Windows events that we don't handle. The code 
for this in in back win32/Win32Server.m. What we could do here is turn 
all events with a number bigger than WM_USER into NSApplicationDefined 
events and pass on the event number in data1. But where would you handle 
that event? Either in the application class or in a specific window. I 
am not sure about NSApplicationDefined events being passed down to the 
control.

If you want do it your way, you can get the native handle from an 
NSWindow by calling the windowNumber method on the window. Just cast the 
returned value to a handle.