MODERN C++: Migrating Legacy Codebases to C++20, C++23, and C++26

Your C++ codebase isn't broken. It's just showing its age. Raw pointers, callback spaghetti, SFINAE templates nobody can read, printf scattered through a million lines of production code - if any of that sounds familiar, this book was written for you. Modern C++ is a complete, practical guide to migrating real-world codebases from legacy C++ to C++20, C++23, and C++26 - without breaking production, losing your team, or spending a year on a big-bang rewrite that never ships. What makes this book different: - Every technique is taught through the problem it solves, not as an isolated feature - Every code example compiles and runs - no pseudocode, ever - Every chapter ends with a Migration Checklist you can apply to your codebase today - Real-world case studies from Bloomberg, Meta, Google, Dropbox, and others show how production teams actually did it - Covers the full arc: C++20 Concepts, Modules, Coroutines, and Ranges - then C++23 std:: expected, std:: format, std:: mdspan - then C++26 Reflection and Contracts You'll learn how to: - Audit a legacy codebase and build a migration plan that won't blow up in production - Replace SFINAE nightmares with readable, enforceable Concepts - Kill header files and slash build times with C++20 Modules - Transform callback hell into clean coroutine pipelines - Replace raw loops with composable, lazy Range pipelines - Eliminate entire bug classes with std:: expected and smart pointers - Say goodbye to printf forever with std:: format and std:: print - Prepare your codebase for C++26 Reflection and Contracts today - Execute a full C++17 to C++26 migration with a phase-by-phase playbook Who this book is for: Professional C++ engineers with production experience who are ready to modernise. This is not a beginner book and it is not a reference manual. It is a field guide for engineers who ship real software and need a concrete, safe, step-by-step plan to bring their codebases into the modern era. "Every chapter must leave the reader feeling: I understand this deeply, I've built something with it, I know where it applies in my codebase, and I can't wait to read the next one." - David Lane