qt-solutions

So far I gathered:

• Windows Internals Book

• MSDN C++ service implementation sample

• Qt-Solutions QtProject/QtService

Problem is that example service from Qt-solutions is not running event loop. It is using QCoreApplication but somehow exec() does not start event loop (something with the threads ?) It must have something to do with project being somewhat old (last real update was added 3 years ago) and Qt 5.10 being somewhat new. Fix is probably not hard but I would like to understand how the whole thing could be designed. I'd prefer to find problem myself but if someone wants to check it I will accept that answer as well.

This is how I understand windows service program should look like:

There are at least two threads in this setup. First one (T1) is created for executable and entry point is usual main() which is supposed to call StartServiceCtrlDispatcher() that blocks. It passes function pointer to service main function. Let's call it SvcMain().

System will create another thread (T2) with entry point being SvcMain() which should as soon as possible run RegisterServiceCtrlHandler() to register another function as service control handler let's call it SvcCtrlHandler() and then do whatever it is supposed to be doing.

In Microsoft example SvcCtrlHandler() signals via SetSignal() / WaitForSingleObject() which is not really useful method as it will block SvcMain execution but that is not important (I think).

Questions are:

1) Qt event loop should be incorporated into second thread. Can this be done simply by creating QCoreApplication and calling exec from SvcMain() ?

2) How service manager will signal service ? Does it run SvcCtrlHandler() in thread T1 ? If that is correct then why I have to register it from T2 ?

3) If above is correct I need to create Qt event in T1 without running Qt event loop, or use some other, windows based, mechanism ?

4) I can talk back to service manager from T2 to signal it back that i've heard it ?