There are a number of units in the component library that provide the underlying support for most of the component libraries. These units include the global routines that make up the runtime library, a number of utility classes such as those that represent streams and lists, and the classes TObject, TPersistent, and TComponent. Collectively, these units are called the VCL/RTL. The VCL/RTL does not include any of the components that appear on the Tool Palette. Rather, the classes and routines in the VCL/RTL are used by the components that do appear on the Tool Palette and are available for you to use in application code or when you are writing your own classes. 

The following topics discuss many of the classes and routines that make up the VCL/RTL and illustrate how to use them.

• Using streams
• Working with files
• Working with .ini files
• Working with lists
• Working with string lists
• Working with strings
• Creating drawing spaces
• Printing
• Converting measurements
• Defining custom variants