atl

The Active Template Library (ATL) is a set of template-based C++ classes that simplify the programming of Component Object Model (COM) objects. The COM support in Visual C++ allows developers to easily create a variety of COM objects, OLE Automation servers, and ActiveX controls. Patterned after the Standard Template Library (STL), ATL includes an object wizard that sets up primary structure of the objects very quickly with a minimum of hand coding.

Controls for the Internet market could have been made with the Microsoft Foundation Classes, but this market requires controls to be small and compact for downloading over the network from Web servers. MFC applications tend to be large and require support DLLs. ATL allows creating smaller controls without support DLLs, so ATL is in a sense a lightweight alternative to MFC for the COM control environment. Apple - Trailers - ATL.

A common use of ATL in ASP was to construct objects that could be called from a script in ASP. VBscript was very limited, but it could call industrial strength C++ windows code contained in a COM object.

With the advent of ASP. NET, which comes with a script language as powerful and nearly as fast as C++, this has become less necessary.

See also