The Component Library for Cross Platform (CLX), is a cross-platform visual component-based framework for developing on [Microsoft Windows] and [Linux] applications. It is developed by Borland for use in its Kylix, Delphi, and C++ Builder software development environment.
The aim of CLX was to replace the existing and popular Microsoft Windows-only framework Visual Component Library (VCL). CLX was based on QT by Trolltech. The API of CLX followed almost completely the VCL. It was envisioned that existing applications using VCL would simply be recompiled with CLX.
This article by Brian Long introduces CLX and makes a comparison between VCL and CLX.
However, due to lacklustre performance on Windows, subtle differences from VCL and bugs it didn't became the expected successor of VCL. Commercial failure of Kylix stopped further development of CLX.
In terms of object oriented approach, the CLX forms an object hierarchy where the TObject class serves as the base class. All other classes inherit or indirectly inherit the TObject class. This is necessary as Delphi does not support multiple inheritance, unlike C++.
Visual CLX is supported until Delphi 7, though there are some efforts to build the (Free)CLX with FPC.
