Top COM DCOM Interview Questions :: ALLInterview.com http://www.allinterview.com Top COM DCOM Interview Questions en-us Define and explain COM? http://www.allinterview.com/showanswers/18201.html COM (Component Object Model) technology in the Microsoft Windows-family of Operating Systems enables software components to communicate. COM is used by developers to create re-usable software components, link components together to build applicat What is In-proc? http://www.allinterview.com/showanswers/16127.html In-proc server is a COM component, when instance is the server is loaded into the caller process space. In-Proc server can be easily identified by .dll extension. Out-of-Proc server is a COM component that run in its own process space and fo Do COM keep track of all the object references(Accounting)? http://www.allinterview.com/showanswers/18202.html yes Differentiate normal DLL to COM DLL http://www.allinterview.com/showanswers/60886.html A normal DLL can export any function. A COM DLL is the one which exports COM APIs like * DllGetClassObject. * DllRegisterServer. * DllUnregisterServer. * DllCanUnloadNow. What happens when client calls CoCreateInstance? http://www.allinterview.com/showanswers/16125.html - Reads Root\Classes\ProgId for the matching ProgID - Reads Root\Classes\ProgId for the matching CLSID. The CLSID is read from the above step. - From the CLSID key, the server type and image filename is known. - Depending upon the server t When you call CoInitialize(NULL) function how it works internally. http://www.allinterview.com/showanswers/60567.html This function is used to initialize a component object model. What is a moniker ? http://www.allinterview.com/showanswers/16129.html An object that implements the IMoniker interface. A moniker acts as a name that uniquely identifies a COM object. In the same way that a path identifies a file in the file system, a moniker identifies a COM object in the directory namespace. what is oops http://www.allinterview.com/showanswers/6883.html Opps is Object oriented programming language. The main aim is to creating an Object to The Entire program and that to we can control entire program using the Object. the main features of OPPS is Polymorphism,Multiple Inheritence,abstraction and What is the difference, if any, between OLE and COM? http://www.allinterview.com/showanswers/16126.html COM is a standard and OLE is build upon that standard What are the purposes of AddRef, Release and QueryInterface function http://www.allinterview.com/showanswers/16122.html To bring the lost object identity back to the component thru QueryInterface and manage the life-cycle of the component thru AddRef and Release by reference counting. What is IUnknown? What methods are provided by IUnknown? http://www.allinterview.com/showanswers/16121.html Iunknow is the base interface for any com component. it supports three methods addref() release() queryinterface() C is aggregated by B, which in turn aggregated by A. Our client requ http://www.allinterview.com/showanswers/16130.html QueryInterface to A will delegate request to B which, in turn, will delegate request for the interface to C. This pointer will be returned to the client. how do you know it is general dll or com dll http://www.allinterview.com/showanswers/64905.html COM Dll contails IUnknown interface but general DLL doesn't. How can would you create an instance of the object in COM http://www.allinterview.com/showanswers/16124.html We can use CreateInstance And CoCreateInstance to create an instance of the object in COM. HRESULT CreateInstance(void* pfnCreateInstance,REFIID riid, void** ppvObj ); Parameters pfnCreateInstance [in] A pointer to a creator function. How to Use structs in COM interfaces when Automation compatibility http://www.allinterview.com/showanswers/16201.html Structs, also known as User Defined Types (UDTs), can be used in Automation- compatible interfaces An Automation- compatible struct may contain only primitive Automation types as its members. Nesting structs is not allowed, but VARIANT is a