VCL and CLX are class libraries made up of objects, some of which are also components or controls, that you use when developing applications. Both libraries look very similar and contain many of the same objects. Some objects in the VCL implement features that are available on Windows only such as objects that appear on the ADO, BDE, QReport, COM+, Web Services, and Servers tabs on the Component palette. Virtually all CLX objects are available on both Windows and Linux.
VCL and CLX objects are active entities that contain all necessary data and the 搈ethods?(code) that modify the data. The data is stored in the fields and properties of the objects, and the code is made up of methods that act upon the field and property values. Each object is declared as a 揷lass.?All VCL and CLX objects descend from the ancestor object TObject including objects that you develop in Object Pascal.