A function that sets or retrieves the value of a property. Most properties have a pair of accessor functions; properties that are read-only may have only one accessor function.

Application object

The top-level object in an application's object hierarchy. The Application object identifies the application to the system and typically becomes active when the application starts. Specified by the appobj attribute in the type library.


class identifier (CLSID)

A UUID that identifies an OLE object. An object registers its CLSID in the system registration database so that it can be loaded and programmed by other applications.

class factory

An object that implements the IClassFactory interface, which allows it to create other objects of a specific class.


Component object model class; a top-level object in the object hierarchy.

collection object

A grouping of exposed objects. A collection object enables you to address multiple occurrences of an object as a unit, for example, to draw a set of points.

component object

A Windows object identified by a unique class identifier (CLSID), which associates the object with a DLL or an .EXE file.

compound document

A document that contains data of different formats, such as sound clips, spreadsheets, text, and bitmaps, created by different applications. Compound documents are stored by container applications.

container application

An application that provides storage, a display site, and access to a compound document object.


Dispatch identifier (DISPID)

The number by which a member function, parameter, or data member of an object is known internally to IDispatch.


An IDispatch interface that responds only to a certain fixed set of names. The properties and methods of the dispinterface are not in the virtual function table (VTBL) for the object.

dual interface

An interface that supports both IDispatch and VTBL binding.



An action recognized by an object, such as clicking the mouse or pressing a key, and for which you can write code to respond. In OLE Automation, an event is a method that is called, rather than implemented, by an OLE Automation object.

event sink

A function that handles events. The code associated with a Visual Basic form, which contains event handlers for one or more controls, is an event sink.

event source

A control that experiences events and calls an event handler to dispose of them.

exposed object

See OLE Automation object.



A value returned from a function call to an interface, consisting of a severity code, context information, a facility code, and a status code that describes the result. For 16-bit Windows systems, the HRESULT is an opaque result handle defined to be zero for a successful return from a function, and nonzero if error or status information is to be returned. To convert an HRESULT into the more detailed SCODE, applications call GetSCode(). See SCODE.


ID binding

The ability to bind member names to DISPIDs at compile time, for example, by obtaining the IDs from a type library. This approach eliminates the need for calls to IDispatch::GetIDsOfNames and results in improved performance over late-bound calls. See also late binding.

in-place activation

The ability to activate an object from within an OLE control and to associate a verb with that activation (for example, edit, play, change). Sometimes referred to as in-place editing or visual editing.

in-process server

An object application that runs in the same process space as the OLE Automation controller.


One or more well-defined base classes providing member functions that, when implemented in an application, provide a specific service. Interfaces may include compiled support functions to simplify their implementation.


late binding

The ability to bind names to IDs at run time, rather than compile time.

local server

An object application implemented in an .EXE file that runs in a separate process space from the OLE Automation controller.

locale identifier (LCID)

A 32-bit value that identifies the human language preferred by a user, region, or application.



The process of packaging and sending interface parameters across process boundaries.

member function

One of a group of related functions that make up an interface. See also method and property.


Member functions of an exposed object that perform some action on the object, such as saving it to disk.

multiple-document interface (MDI) application

An application that can support multiple documents from one application instance. MDI object applications can simultaneously service a user and one or more embedding containers. See also single-document interface (SDI) application.



A unit of information that resides in a compound document and whose behavior is constant no matter where it is located or used.

Object Description Language (ODL)

A scripting language used to describe exposed libraries, objects, types, and interfaces. ODL scripts are compiled into type libraries by the MkTypLib tool.


An acronym for Object Linking and Embedding.

OLE Automation

A technology that provides a way to manipulate objects defined by an application or library from outside the application. OLE Automation enables programmability.

OLE Automation controller

An application, programming tool, or scripting language that accesses OLE Automation objects. Visual Basic is an OLE Automation controller.

OLE Automation object

An instance of a class defined within an application that is exposed for access by other applications or programming tools by means of OLE Automation interfaces.

OLE Automation server

An application, type library, or other source that makes OLE Automation objects available for programming by other applications, programming tools, or scripting languages.


programmable object

See OLE Automation object. property

A data member of an exposed object. Properties are set or returned by means of get and put accessor functions.


An interface-specific object that packages parameters for that interface in preparation for a remote method call. A proxy runs in the address space of the sender and communicates with a corresponding stub in the receiver's address space. See also stub, marshaling, and unmarshaling.


safe array

An array that contains information about the number of dimensions and the bounds of its dimensions. Safe arrays are passed by IDispatch::Invoke within VARIANTARGs. Their base type is VT_tag | VT_ARRAY.


A DWORD value that is used to pass detailed information to the caller of an interface member or API function. The status codes for OLE interfaces and API's are defined in FACILITY_ITF. See HRESULT.

single-document interface (SDI) application

An application that can support only one document at a time. Multiple instances of an SDI application must be started to service both an embedded object and a user. See also multiple-document interface (MDI) application.


An interface-specific object that unpackages the parameters for that interface after they are marshaled across the process boundary, and makes the requested method call. The stub runs in the address space of the receiver and communicates with a corresponding proxy in the sender's address space. See proxy, marshaling, and unmarshaling.

type description

The information used to build the type information for one or more aspects of an application's interface. Type descriptions are written in Object Description Language (ODL) and include both programmable and nonprogrammable interfaces.

type information

Information that describes the interfaces of an application. Type information is created from type descriptions using OLE Automation tools, such as MkTypLib or the CreateDispTypeInfo function. Type information may be accessed through the ITypeInfo interface.

type information element

A unit of information identified by one of these statements in a type description: typedef, enum, struct, module, interface, dispinterface, or coclass.

type library

A file or component within another file that contains type information. Type libraries are created from type descriptions using MkTypLib, and may be accessed through the ITypeLib interface.



The process of unpackaging parameter that have been sent across process boundaries.


Value property

The property that defines the default behavior of an object when no other methods or properties are specified. You indicate the Value property by specifying the default attribute in ODL.

  • irtual function table (VTBL)

A table of function pointers, such as an implementation of a class in C++. The pointers in the VTBL point to the members of the interfaces that an object supports.

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