Which inrerface is the default for Windows and how to change it?

[dodgebros]

If I understand correctly there are three different interfaces one can use to create MS Windows apps in Lazarus, Win32 API, QT4, and GTK.

My questions:

1. Which one is used in the default installation of Lazarus?

2. Do I need to purchase a license to use the QT4 interface?

3.  If I decide to use the Win32 API interface, how do I make that change in Lazarus?

I am running Lazarus on Windows XP SP3 and Windows 7.

Thanks,
TD

[rvk]

1. Which one is used in the default installation of Lazarus?

Default on Windows is Win32 API

2. Do I need to purchase a license to use the QT4 interface?

Not if you don't use it, of course . I don't know otherwise and it probably would depend on your license and distribution method of the necessary files. See the questionnaire at http://www.qt.io/download/ and read the license.

3.  If I decide to use the Win32 API interface, how do I make that change in Lazarus?

It's already standard. You're using it right now 
Look under Project > Project Options > Compiler Options > Config and Target