What Does Active Template Library (ATL) Mean?
Active Template Library is a group of Microsoft C++ template classes (program routines) that are specifically designed to simplify Component Object Model (COM) and ActiveX development and coding. Responding to market demand for compact and easily downloadable objects, Microsoft introduced ATL as a lightweight technology to complement Microsoft Foundation Classes (MFC).
ATL is formerly known as ActiveX Template Library (ATL).
Techopedia Explains Active Template Library (ATL)
Based on the Standard Template Library (STL), ATL extends the Visual Studio development environment with wizards used for COM object automation. ATL facilitates the programming of COM objects for script invocation by Active Server Pages (ASP).
ATL may be used to create a variety of objects, including dialog boxes and Internet Explorer controls. ATL supports key COM features, such as ActiveX controls, dual interfaces and connection points.