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3.10.1 What are COM/ActiveX objects?

The Component Object Model

The Microsoft Developer Network (MSDN) is an important source of information for developers about Microsoft technologies. The MSDN Library (October 1999 edition) defines COM as follows:

The Component Object Model (COM) is a platform-independent, distributed, object-oriented, system for creating binary software components that can interact. COM is the foundation technology for Microsoft's OLE (compound documents), ActiveX (internet enabled components), as well as others.

Overview Of Automation

The MSDN Library (October 1999 edition), and defines Automation follows:

Automation (formerly called OLE Automation) is a technology that allows software packages to expose their unique features to scripting tools and other applications. Automation uses the Component Object Model (COM), but may be implemented independently from other OLE features, such as in-place activation. Using Automation, you can:

  1. Create applications and programming tools that expose objects.
  2. Create and manipulate objects exposed in one application from another application.
  3. Create tools that access and manipulate objects. These tools can include embedded macro languages, external programming tools, object browsers, and compilers.
The objects an application or programming tool exposes are called ActiveX objects. Applications and programming tools that access those objects are called ActiveX clients. ActiveX objects and clients interact as follows:

Applications and other software packages that support ActiveX technology define and expose objects which can be acted on by ActiveX components. ActiveX components are physical files (for example .exe and .dll files) that contain classes, which are definitions of objects. Type information describes the exposed objects, and can be used by ActiveX components at either compile time or at run time.

Irie Pascal and ActiveX objects

Irie Pascal accesses the type information about exposed ActiveX objects at run time only. At compile time Irie Pascal does not know anything about the names or types of the objects' methods or properties.

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