1.3 Overview
The Object Linking and Embedding (OLE) Property Set Data Structures (OLEPS) enable applications to write metadata in a manner that is discoverable to other software. A property set consists of a set of properties, each of which is a typed value associated with a numerical property identifier, and a globally unique identifier (GUID) format identifier, or FMTID, which can be used to identify the semantics and expected usage of the properties.
Certain FMTIDs correspond to well-known, published property set formats, while other property set formats are application-defined. If an application defines its own property set format or formats, the developer of the application will typically publish (through an out-of-band mechanism) the application-defined formats and FMTIDs so that other software can recognize and use the properties in a meaningful way. In either case, the semantics and expected usage of properties in a property set are dependent on the property set format. This document does not specify the semantics of properties or assignment of property identifiers in general, nor does it specify the mechanism to be used for publishing property set formats.
The OLE Property Set Data Structures Specification consists of the following:
The specification for storing a property set as a stream or storage (2) suitable for use with a file format or other storage (2) technology that provides containers for these abstract types.
Standard bindings for storing property set streams and storages (1) in a compound file (for details see [MS-CFB]), and for storing property sets in alternate streams of a file, in file systems that provide such a feature. An example of a file system that provides alternate streams is NTFS (for more information, see [MSDN-FileStreams] ).
The specifications for the well-known property set formats, PropertyIdentifier and PropertyBag.