GTDIO is supplied with a COM (Component Object Module) object library in addition to the function described in the prior section. The library is used to create and modify DIO files and interface with the DIOEasy application. COM is a Microsoft standard for describing, interfacing and using programmable classes and objects. COM provides a more object oriented programming methodology towards programming then procedural by combining the object code and data to one entity. The COM library describe the classes and their methods, properties and events and additional data types such as enumerated types and structures are defined. COM object classes have methods and properties. Methods are similar to functions calls however they operate on the object which they are called on. Properties are similar to data members and are used to set the object characteristic. Some properties are read only (return only) and cannot be changed, some others can be read and write (returns or set).
The examples provided in this chapter are written in Microsoft Visual Basic version 6.0. Similar code can be used in other languages that support COM including ATEasy, C/C++ and .NET based languages.