OWL, a similar framework to MFC, required writing code to create UI objects.
A key aim of the VCL combined with the Delphi language was to change the requirements of building a user interface.
(For context, the Delphi variant of Pascal had a number of innovative object-oriented features, such as properties and runtime type information, inspired by Modula and Smalltalk.)
)[1] UI code was also complicated, forcing the programmer to understand and use the Windows API, manage GDI resources, etc.
The VCL is Windows-based and its implementations of common controls are wrappers of the Windows API, thus is close to the ground and fully native.
Today the VCL includes several hundred visual and non-visual components, usable in both the Delphi and C++ languages.
[8] A cross-platform equivalent of the VCL, called CLX (Component Library for Cross Platform), was later developed for use in Delphi, C++Builder and Kylix in 2000–2001.
The Lazarus project has a portable (*nix, OS/X, Win32/64+wince) equivalent called LCL, which was already working when Kylix and CLX emerged.