Meeting C++ 2026 - Opening Keynote: Why Great C++ Libraries Fail (And How to Fix That)

Mateusz Pusz

On Day 1 at 10:00 (CET/Berlin) in Track A [Saphir Room and online]

A participant at one of my workshops asked: "Which open source project should I contribute to if I want to learn Modern C++?" The answer was "it depends": on the documentation, on the community, on whether a newcomer can build the project at all. Many technically brilliant C++ libraries are built like a fortress: the README starts with "First, install Clang 18, CMake 3.28...", the only documentation is "Read the source, Luke", the maintainers reply "This is the correct design. Period.", and there is no clear path for contributors.

The language now has concepts, ranges, and constexpr almost everywhere, and adopting a C++ library is still where many people give up. Users hit the friction and write their own. Contributors move to ecosystems that welcome them. Companies stay on twenty-year-old code because nobody made the new option easy to try. Technical excellence goes unused.

This keynote follows a user through six stages: Discovery, Evaluation, Understanding, Integration, Contribution, and Community. At each stage, we look at why people leave and what to change so they stay, with mp-units as the running example of a project that went from a hobby to a library proposed for the C++ standard. Expect a README that passes the five-second test, a randomized build matrix whose modules and freestanding builds catch the missing export and the accidental before your users do, and documentation organized with the Diátaxis framework instead of a Doxygen API reference and nothing else. The talk also covers Compiler Explorer links, GitHub Codespaces for one-click setup, CMake targets and Conan packages, release notes in prose, and a contribution policy for the growing stream of AI-generated pull requests.

Whether you use other people's libraries, want to contribute to one, or maintain your own, you will leave with a checklist of eleven changes. Don't start with all eleven: pick one and spend two hours on it this week.

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