ATL Module Classes

This topic discusses the module classes that were new in ATL 7.0.

CComModule Replacement Classes

Earlier versions of ATL used CComModule. In ATL 7.0, CComModule functionality is replaced by several classes:

CAtlBaseModule Contains information required by most applications that use ATL. Contains the HINSTANCE of the module and the resource instance.
CAtlComModule Contains information required by the COM classes in ATL.
CAtlWinModule Contains information required by the windowing classes in ATL.
CAtlDebugInterfacesModule Contains support for interface debugging.
CAtlModule The following CAtlModule-derived classes are customized to contain information required in a particular application type. Most members in these classes can be overridden:
- CAtlDllModuleT Used in DLL applications. Provides code for the standard exports.
- CAtlExeModuleT Used in EXE applications. Provides code required in an EXE.
- CAtlServiceModuleT Provides support to create Windows NT and Windows 2000 Services.

CComModule is still available for backward compatibility.

The functionality of CComModule was distributed into several new classes for the following reasons:

Make the functionality in CComModule granular.

Support for COM, windowing, interface debugging, and application-specific (DLL or EXE) features is now in separate classes.
Automatically declare global instance of each of these modules.

A global instance of the required module classes is linked into the project.
Remove the necessity of calling Init and Term methods.

Init and Term methods have moved into the constructors and destructors for the module classes; there is no longer a need to call Init and Term.