Windows Programming COM and ActiveX

 10 May 10:10   

    People accustomed with Windows accept absolutely heard a amount of altered agreement used, such as COM, DCOM, COM+, ActiveX, OLE, etc. What absolutely are all these things, and how are they related?

    COM is the accepted name for a adjustment of language-neutral item aggressive programming. COM about lays a framework for classes to be created in any language, and to be instantiated into any additional languages. A chic may be accounting in C++, and alleged from VisualBasic, et cetera. Essentially, COM defines an interface that all languages haveto follow, if they wish to participate in COM programs. The acronym stands for Basic Item Model, and works like a accepted framework for alotof of Windows to operate.

    ActiveX is the name for Microsofts specific cast of COM. For instance there is a accepted affair in this apple alleged car, and there are assorted altered brands of car (Audi, BMW, Ford...). A Ford is a car, just like an Audi is a car. Likewise, there may be some altered brands of COM. ActiveX is the COM that Microsoft made.

    OLE is a appellation that has had some meanings and uses. A accepted acronym for OLE is Item Bond and Embedding, which was infact a alternative of COM. However, the appellation OLE has been acclimated to call some altered things over the years, and it can be actual ambagious to humans still.

    COM classes, accounting in a compileable accent (such as C++ or VisualBasic) may be aggregate into DLL libraries. DLL libraries that accommodate COM classes are not accordant with DLL libraries accounting in C that accommodate approved C functions. However, DLL files may be aggregate that accommodate both accepted C functions, and COM classes.

    Files that accommodate COM classes are refered to as COM modules, or COM Components. Just like with additional activating bond applications, Windows will administer the COM interface amid apparatus automatically, so continued as all the modules appropriately use the COM specifications.

    The COM arrangement relies on after identifiers understand as Universally Different Identifiers (UUID). A UUID is a 128 bit amount that is about affirmed to be different COM identifier throughout the absolute world. The UUID amount is a assortment amount based off the MAC abode of your primary arrangement agenda (if your computer has one) and the real-time alarm amount of your processor. This agency that the alone way to accomplish 2 UUIDs that are identical would be to accomplish both at absolutely the aforementioned time on absolutely the aforementioned computer. Thankfully, this is absurd to do.

    COM apparatus are accustomed a UUID number, so that they can be differentiated from all additional COM components, and any accustomed COM bore can be articular by a individual numeric identifier.