COM/MTS Guide - Prolifics

COM Features! Security for component access. Defining roles on the MTS server determineswhich users can access the COM components in a given package.COM FeaturesUnique IdentifiersWhen you create a COM component, Panther automatically assigns it a CLSID (classidentifier) based on your network card ID, the current time, and other data. (Anotherterm for CLSID is GUID—globally unique identifier.) When a COM component isregistered on your machine, its CLSID is written into the system registry.In addition to identifying the COM component, the CLSID has another use. Wheneveryou modify a component's interface, you should assign the component a new CLSID.This guarantees the behavior of COM components. If you find COM components withthe same CLSID, you then know that both components have the same interfaces,properties, and methods.Defined InterfacesWhen you create a COM component, you define the interfaces that the component willsupport. An interface is a collection of:! Methods (or functions) that you can call in order for the component to completesome action.! Properties that you can query and set.All COM components support the IUnknown interface; one of the methods in theIUnknown interface, QueryInterface, allows you to ask the COM component whichother interfaces it supports. Since COM components are encapsulated, not allowingaccess to their internal implementation, interfaces are the only way to access a COMcomponent.COM/MTS Guide 1-3