COM Objects and Interfaces

COM is a technology that allows objects to interact across process and computer boundaries as easily as within a single process. COM enables this by specifying that the only way to manipulate the data associated with an object is through an interface on the object. When this term is used in this documentation, it refers to an implementation in code of a COM binary-compliant interface that is associated with an object.

COM uses the word interface in a sense different from that typically used in Visual C++ programming. A C++ interface refers to all of the functions that a class supports and that clients of an object can call to interact with it. A COM interface refers to a predefined group of related functions that a COM class implements, but a specific interface does not necessarily represent all the functions that the class supports.

Referring to an object implementing an interface means that the object uses code that implements each method of the interface and provides COM binary-compliant pointers to those functions to the COM library. COM then makes those functions available to any client who asks for a pointer to the interface, whether the client is inside or outside of the process that implements those functions.

For more information, see the following topics: