ATL Concepts

The Active Template Library (ATL) is a set of template-based C++ classes that let you create small, fast Component Object Model (COM) objects. It has special support for key COM features, including stock implementations, dual interfaces, standard COM enumerator interfaces, connection points, tear-off interfaces, and ActiveX controls.

If you do a lot of ATL programming, you will want to learn more about attributes, a new feature in Visual C++ .NET that is designed to simplify COM programming. For more information, see Attributed Programming.

In This Section

• ATL Tutorial
  Leads you through the creation of a control and demonstrates some ATL fundamentals in the process.

• Introduction to COM and ATL
  Introduces the major concepts behind the Component Object Model (COM). This article also briefly explains what ATL is and when you should use it.

• Fundamentals of ATL COM Objects
  Discusses the relationship among various ATL classes and how those classes are implemented.

• Dual Interfaces and ATL
  Describes dual interfaces from an ATL perspective.

• ATL Collections and Enumerators
  Describes the implementation and creation of collections and enumerators in ATL.

• Composite Control Fundamentals
  Provides step-by-step instructions for creating a composite control. A composite control is a type of ActiveX control that can contain other ActiveX controls or Windows controls.

• ATL Control Containment FAQ
  Covers the fundamental questions related to hosting controls with ATL.

• ATL COM Property Pages
  Shows you how to specify and implement COM property pages.

• ATL Support for DHTML Controls
  Provides step-by-step instructions for creating a DHTML control.

• ATL Connection Points
  Explains what connection points are and how ATL implements them.

• Event Handling and ATL
  Describes the steps that you need to take to handle COM events using ATL's IDispEventImpl and IDispEventSimpleImpl classes.

• ATL and the Free Threaded Marshaler
  Provides details on the ATL Simple Object Wizard's option that allows your class to aggregate the free threaded marshaler (FTM).

• Specifying the Project's Threading Model
  Describes the macros that are available to control run-time performance related to threading in your project.

• ATL Module Classes
  Discusses the module classes new for ATL 7.0. Module classes implement the basic functionality required by ATL.

• ATL Services
  Covers the series of events that occur when a service is implemented. Also talks about some of the concepts related to developing a service.

• ATL Window Classes
  Describes how to create, superclass, and subclass windows in ATL. The ATL window classes are not COM classes.

• ATL Collection Classes
  Describes how to use arrays and maps in ATL.

• The ATL Registry Component (Registrar)
  Discusses ATL scripting syntax and replaceable parameters. It also explains how to set up a static link to the Registrar.

• Programming with ATL and C Run-Time Code
  Discusses the benefits of linking statically or dynamically to the C Run-Time Library (CRT).

• Programming with CComBSTR
  Discusses several situations that require caution when programming with CComBSTR.

• ATL Encoding Reference
  Provides functions and macros that support encoding in a range of common Internet standards such as uuencode, hexadecimal, and UTF8 in atlenc.h.

• ATL Utilities Reference
  Provides code for manipulating paths and URLs in the form of CPathT and CUrl. A thread pool, CThreadPool, can be used in your own applications. This code can be found in atlpath.h and atlutil.h.

Related Sections

• ATL Samples
  Provides descriptions of and links to the ATL sample programs.

• Creating an ATL Project
  Contains information on the ATL Project Wizard.

• ATL Control Wizard
  Discusses how to add classes.

• Breaking Changes in ATL 7.0 and MFC 7.0 Since Visual C++ 6.0
  Lists items to take into account when updating code from previous versions to ATL 7.0.

• Attributed Programming
  Provides an overview on using attributes to simplify COM programming plus a list of links to more detailed topics.

• ATL Class Overview
  Provides reference information and links to the ATL classes.