[vwnc] ServiceStartup & WinService[Interface]

When the user tries to shutdown, restart or log off, Windows sends the WM_QUERYENDSESSION  (16r11 = 17) message to all applications. The VM responds true or false to WM_QUERYENDSESSION depending on the value of acceptQuitEvents. Note that the VM responds: the image doesn't get a chance to intervene. From Windows' point of view, if all applications return true then the shutdown proceeds; if any return false (zero), the shutdown is not started and Windows stops asking any remaining applications. However, the applications that replied true will still be closed with WM_ENDSESSION (apparently: the Windows docs seem to contradict each other on this).

Regardless of the result of WM_QUERYENDSESSION, Windows sends WM_ENDSESSION (16r16 = 22) to all windows, passing the overall result as a Boolean in wParam. If you want a VW window to receive WM_ENDSESSION, add the following in its postOpenWith: method:

                aBuilder window application: self.

                aBuilder window sendWindowEvents: #(#eventUnknown)

In its windowEvent:from: method you can then add:

               (anEvent key == #eventUnknown and: [Screen default platformName = 'MS-Windows' and: [((anEvent value at: 10) longAt: 9) = 22]])

                                ifTrue: [self closeRequest]

The ifTrue: action can of course be whatever you want. The test is probably not quite right, because we should also check that wParam is true – remember WM_ENDSESSION is sent even if some app refused WM_QUERYENDSESSION and hence Windows will not actually shut down. Here are the contents of "anEvent value" in that case:

#(0 2469 0 0 0 0 0 0 0 #[0 0 0 0 165 9 0 0   22 0 0 0    0 0 0 0   0 0 0 0] 0 nil nil nil nil nil)

I guess longAt: 13 will be wParam and longAt: 17 will be lParam (I'm assuming 32-bit Windows here: in 64-bit, I think HWND is 64 bits, not sure about the others). So maybe an extra check:

((anEvent value at: 10) longAt: 13) ~= 0

before deciding to do whatever pre-shutdown tidying up your app requires.

I don't know what your hex 3B is: it's not listed anywhere that I could find.

The details are here:

http://msdn.microsoft.com/en-us/library/aa376890(VS.85).aspx

Finally, note this all applies to normal GUI apps. If you have a console app or a service, shutdown notification is different. For services, see WinService in the public repository: call it with something like this:

[              interface := WinServiceInterface new.

                interface

                                startDispatcherWithHandler:

                                                [:event |

                                                (event = interface SERVICE_CONTROL_STOP

                                                or: [event = interface SERVICE_CONTROL_SHUTDOWN])

                                                                ifTrue:

                                                                                ["ADD YOUR SERVICE SHUTDOWN CODE HERE"]]

                                serviceName: serviceName

                                startupBlock:

                                                ["ADD YOUR SERVICE STARTUP CODE HERE"]

] fork

HTH,

Steve