Chapter 5: Libraries, Packages, and Components

There's a joke listed as one of Murphy's computer laws that goes like this:

Any given program will expand to fill all the available memory.

Over the life of an application, customers demand more, operating systems get updated, new devices are supported, and so on. It is inevitable that useful software will grow in size and complexity over time.

Today's programs share code, call external services, and dynamically load resources in a variety of ways. Delphi has supported these techniques for a long time, but a refresher is in order, not only because it's more important than ever but also because there are some cross-platform considerations.

We'll start with the basics by simply pulling out procedures and functions into a Dynamically Loaded Library (DLL) that can be called from any language. Then, we'll move to working with packages and show you how to install your own custom components into Delphi...