Uploaded November 2025 | Updated September 2026, 2 weeks ago
cppcon.org
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Implement the C++ Standard Library: Design, Optimisations and Testing while Implementing Libc++ - Hui Xie - CppCon 2025
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This presentation covers various practical examples in the designs, optimisations and testing in libc++, a standard library implementation.
In space optimisation section, it presents various examples of using compact type, reusing tail padding bytes, reusing unused bits in existing bytes, in various standard types: std::stop_token , std::expected , std::optional , std::variant , std::ranges library and std::move_only_function .
In time optimisations section, it presents examples of how we optimise std::atomic＜T＞::wait 's waiting strategy, how we optimised algorithms for segmented iterators, and also how we keep in mind optimisations by leaving the door open for future optimisations. At the same time, compilation time is also important so it also contains examples how unnecessary template instantiations can be avoided.
Finally, this talk covers the unit tests of libc++, including the high test coverage of standard spec, the technique we share tests between runtime and constexpr, negative testing and so on.
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Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Implement_Standard_Library.pdf
Video Sponsored by Susquehanna - youtube.com/@LifeatSusquehanna
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
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Hui Xie
Hui Xie is a C++ software developer at Qube Research and Technologies in the finance industry. He is a member of the standard committee WG21 and the UK national body BSI. He usually contributes to the ranges study group SG9. He is also an active contributor to libc++, the clang's standard library implementation.
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CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
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Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
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#cpp #cplusplus #cppcon #cppprogramming #cplusplusprogramming #softwaredevelopment #softwareengineering #coding #code #computerscience #technology #technews #programming #programmer
cppcon.org
---
Implement the C++ Standard Library: Design, Optimisations and Testing while Implementing Libc++ - Hui Xie - CppCon 2025
---
This presentation covers various practical examples in the designs, optimisations and testing in libc++, a standard library implementation.
In space optimisation section, it presents various examples of using compact type, reusing tail padding bytes, reusing unused bits in existing bytes, in various standard types: std::stop_token , std::expected , std::optional , std::variant , std::ranges library and std::move_only_function .
In time optimisations section, it presents examples of how we optimise std::atomic＜T＞::wait 's waiting strategy, how we optimised algorithms for segmented iterators, and also how we keep in mind optimisations by leaving the door open for future optimisations. At the same time, compilation time is also important so it also contains examples how unnecessary template instantiations can be avoided.
Finally, this talk covers the unit tests of libc++, including the high test coverage of standard spec, the technique we share tests between runtime and constexpr, negative testing and so on.
---
Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Implement_Standard_Library.pdf
Video Sponsored by Susquehanna - youtube.com/@LifeatSusquehanna
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
---
Hui Xie
Hui Xie is a C++ software developer at Qube Research and Technologies in the finance industry. He is a member of the standard committee WG21 and the UK national body BSI. He usually contributes to the ranges study group SG9. He is also an active contributor to libc++, the clang's standard library implementation.
---
CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
---
Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
---
#cpp #cplusplus #cppcon #cppprogramming #cplusplusprogramming #softwaredevelopment #softwareengineering #coding #code #computerscience #technology #technews #programming #programmer
