Introduction to ATL

ATL is the Active Template Library, a set of template-based C++ classes with which you can easily create small, fast Component Object Model (COM) objects. It has special support for key COM features including: stock implementations of IUnknown, IClassFactory, IClassFactory2 and IDispatch; dual interfaces; standard COM enumerator interfaces; connection points; tear-off interfaces; and ActiveX controls.

ATL code can be used to create single-threaded objects, apartment-model objects, free-threaded model objects, or both free-threaded and apartment-model objects.

Topics covered in this section include:

• How a template library differs from a standard C++ library.
  
  
• What you can and cannot do with ATL.
  
  
• When to use ATL versus MFC.