CppCon 2026

C++ library maintainers are often in the dark as to everyone who actually depends on their code. Without that knowledge, deprecation decisions are guesses, the downstream impact of any API change is hard to predict, and the case for funding or continued investment is difficult to make rigorously. This talk demonstrates how mapping your downstream ecosystem changes the way you maintain and evolve a library, using dependent-audit, an open-source tool that discovers real-world dependents by searching public source code for #include directives and CMake integration files, and cross-referencing published academic citations. We'll show concrete examples of what this data reveals: where your true API surface lies, which users are candidates for upstream contribution, and how to make the case for your project's real-world significance. Attendees will leave with a lens for library stewardship built on data and ecosystem analysis