Adventures with C++ Legacy Codebases: Tales of Incremental Improvement

This conference talk from CppCon 2024 features Roth Michaels sharing practical experience and strategies for improving legacy C++ codebases through incremental changes. Explore real-world examples from the merger of three companies with 20+ year old codebases, divided into two main sections: techniques for making incremental improvements to large legacy systems (including adopting static analysis, adding test coverage, updating conventions, and fixing undefined behavior) and pragmatic approaches for sharing and reusing C++ code from legacy environments. Learn methods ranging from source code sharing to DLL boundary isolation, with examples covering both simple code extraction and handling libraries with deep legacy dependencies. Presented by Roth Michaels, Principal Software Engineer at Native Instruments, who brings extensive experience in merging engineering organizations and legacy codebases across Brainworx, iZotope, and Native Instruments.