The journey to "/W4 /WX": How hard could it be?

Keith Stockdale

⏱ 90 minute session
beginner
intermediate
10:45-12:15, Friday, 19th June 2026

Building on the recent work of improving the quality of Sea of Thieves' codebase by upgrading from C++14 to C++20, this talk will focus on the work that has went into enabling warnings as errors on the game, and more.

Rare will discuss the motivations behind wanting to crank up the warning level, and to flick the "warnings as errors" switch after 10 years of development in their multi-million line Unreal Engine code base.

What were the challenges? How much effort did it take? Was it worth it? Did we find any bugs? Did we stop at just "/W4 /WX"? What warnings did we find the most useful? What warnings were deemed unhelpful? All of these questions and probably more will be answered throughout this session.


🏷 games
🏷 C++20
🏷 Unreal Engine
🏷 Visual C++
🏷 MSVC
🏷 cross-platform
🏷 warnings
🏷 warnings as errors
🏷 /WX
🏷 -Werror

Keith Stockdale

Keith is a Northern Irish senior software engineer who has been working on the Engine and Rendering teams at Rare Ltd for the last 9 years. He primarily works on Engine and Rendering level systems involving General Purpose GPU systems such as GPU particle systems. Keith is enthusiastic about promoting writing good quality code, whether it is running on the CPU on the GPU.