Working with Packages and Components - Overview
A package is a special dynamic-link library used by applications, the IDE, or both. Run-time packages provide functionality when a user runs an application. Design-time packages are used to install components in the IDE and to create special property editors for custom components. A single package can function at both design time and run time, and design-time packages frequently work by calling run-time packages. To distinguish them from other DLLs, package libraries are stored in files that end with the .bpl (Borland package library) extension.
Like other run-time libraries, packages contain code that can be shared among applications. For example, the most frequently used VCL components reside in a package called vcl . Each time you create a new default VCL application, it automatically uses vcl. When you compile an application created this way, the application's executable image contains only the code and data unique to it; the common code is in the run-time package called vclnnn.bpl. A computer with several package-enabled applications installed on it needs only a single copy of vclnnn.bpl, which is shared by all the applications and the IDE itself.
Several run-time packages encapsulate VCL components while several design-time packages manipulate components in the IDE.
You can build applications with or without packages. However, if you want to add custom components to the IDE, you must install them as design-time packages.
You can create your own run-time packages to share among applications. If you write Delphi components, you can compile your components into design-time packages before installing them.
- Making Cross-Platform Components Available at Design Time and Run Time
- Overview of Component Creation
- Why Use Packages
- Packages and Standard DLLs
- Runtime Packages
- Loading Packages in an Application
- Loading Packages with the LoadPackage Function
- Deciding Which Runtime Packages to Use
- Custom Packages
- Design-time Packages
- Installing Component Packages
- Creating and Editing Packages
- Creating a Package
- Editing an Existing Package
- Understanding the Structure of a Package
- Editing Package Source Files Manually
- Compiling Packages
- Package-specific Compiler Directives
- Using the Weak Packaging Directive
- Compiling and Linking from the Command Line
- Package Files Created by Compiling
- Deploying Packages