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Any client that supports the Component Object Model (COM) can access and manipulate Microsoft Visio objects. Several development environments that are available commercially, such as Microsoft Visual Basic, conceal the details of COM, which appeals to many developers. But if you are prepared to work more closely with COM, you can use C or C++ to develop programs that control instances of Visio.
This chapter assumes that you are familiar with COM programming concepts, obtaining pointers to interfaces, and calling interface functions. It also assumes that you are familiar with the C++ programming language. For details about Automation, see the Automation documentation in the Microsoft Platform Software Development Kit (SDK) on MSDN (msdn.microsoft.com). For details about C++, see your C++ documentation.
This chapter discusses how Visio exposes objects to Automation in terms of COM. It describes basic support services provided by Visio; these services ease the task of developing C++ programs that control Visio instances. The chapter then explains how to develop a Visio library (VSL), a type of dynamic-link library (DLL) that a Visio instance loads at run time.
Note
For details about recompiling existing programs to use the new support services or about programming Visio with C, see the Readme.txt file located in \Libraries\C-CPP on the Developing Microsoft Visio Solutions CD.