CODEWITHSUNDEEP
c++qtapiwinapi
user2806369
user2806369

Reputation: 35

Compiled Qt for windows is win api at Low Level

Qt is cross platform c++ Gui Library.Code once and compile for different Platform. Let's for instance, I have compiled a Project(decent text editor with few tool bar) or any such program for Windows(x86).

Statement 1: The Program.exe entry point will be WinMain.

Statement 2: The Text editor and tool bar will created using "CreateWindow" win32 api. Qt have its own class to implement but to ask OS(Windows) for creating a tool bar or text editor, Program exe interface with OS(Windows). OS understand what it know it does not know anything about Qt class,so to create tool bar or text editor program have to use win32 api.

Statement 3: All event processing( button click, mouse click) will handles using windows messeging system.

Note: It may seem i am viewing every thing with win32 api glass on my understanding.

Upvotes: 2

Views: 387

Answers (1)

Kuba hasn't forgotten Monica
Kuba hasn't forgotten Monica

Reputation: 98545

  1. Correct. The WinMain implementation is provided by the Qt library.

  2. Half correct. The top-level windows are created using CreateWindow. Child widgets, such as a non-toplevel toolbar are Qt's own widgets and are opaque outside of your application. They are exposed only via the accessibility APIs. This allows you to create more widgets than Windows would be able to deal with. A million child widgets is doable, if not particularly fast.

  3. Correct - there's no other way. Of course Qt immediately translates native messages into QEvent instances and dispatches them internally to various QObject instances. In Qt-land, all events must be received by a QObject instance.

You're incorrect in your assertion that winapi has anything to do with the kernel. Winapi is implemented by a bunch of user-space DLLs. You could implement those DLLs yourself. Those DLLs themselves call into the kernel using the native api. That's the API actually exposed by the kernel to the user space.

Upvotes: 6

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