What is the difference between OCX API and DLL API?

What is the difference between OCX API and DLL API?

The Applications Programming Interface (API) are the tools provided for use from a programming language such as Visual Basic, Delphi or VC++. Microsoft Windows supports both the use of dynamic link libraries (DLL) or, more recently, ActiveX Controls. ActiveX controls usually have the ocx file extension so have come to be known as OCX controls. Visual Basic and Delphi typically use ActiveX controls, but can use DLLs. Visual C++ typically makes calls to the functions in a DLL, but can also use ActiveX controls. DriverLINX provides both a DLL and an OCX API