> For the complete documentation index, see [llms.txt](https://docs.intrepidcs.com/vspy-3-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.intrepidcs.com/vspy-3-documentation/vehicle-spy-tutorials/tutorial-c-code-interface.md). # Tutorial: C Code Interface ### Overview This application note describes the basics of using the C Code Interface for Vehicle Spy. To use the C Code Interface, an install of Visual C++ Express or better, version 2005 or better is required. The Express Edition can be acquired from [Microsoft's website](https://www.microsoft.com/en-in/) for free. This tutorial does require some knowledge of C programming and familiarity with Visual Studio. In this example Visual C++ Express 2008 will be used. ### Parts of Vehicle Spy used [C Code Interface](/vspy-3-documentation/vehicle-spy-main-menus/main-menu-scripting-and-automation/c-code-interface.md)\ Message Editor\ Application signals --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.intrepidcs.com/vspy-3-documentation/vehicle-spy-tutorials/tutorial-c-code-interface.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.