[DelphiABall]

Delphi has make it very easy to call the Windows API, COM and WinRT, with wide coverage, and encapsulates some of the complexities to make it easier for developers, as you would expect from any good programming tooling today.

Where it gets very cleaver is actually in the way OOP/components are used under the hood to already make many modern features cross-platform ready!

e.g. The same component used by developers for linking to the Notifications API's on Windows 10, works on Android, iOS and macOS! Under the hood, Interfaces are providing back the platform specific implementation, but at a high level you just work with the same component in code, making it very fast to develop cross platform.

The same is true of the RTL for parallel programming, file access etc. - This is thanks to the way API's get encapsulated. I hope that answers the question.

[simion314]

Thanks for trying to respond, it was clear to me that Delphi is similar with Qt ,Java and .Net and encapsulates platform specific stuff in OOP components. My question was why Delphi over C# ? The answer seems to be that if you don't want or can't use the .Net runtime dependency, or maybe if you want small binary size or small memory usage.

My conclusion is that for Windows only GUI there is no major advantage in favor of Delphi, .Net has more tools and libraries. For cross platform it seems Delphi has a superior story though with official support for GUIs on major platforms so is more similar to the Qt Toolkit (Qt also includes a GUI designer and non GUI related components).