C++26 is done! — Trip Report: March 2026 ISO C++ Standards Meeting
News flash: C++26 is done! On Saturday, the ISO C++ committee completed technical work on C++26 in London Croydon, UK. 210 attendees (130 in-person, 80 remote), 24 nations. 411 national body comments resolved.
The Fab Four Features
(1) Reflection
By far the biggest upgrade for C++ development since the invention of templates. For the first time, C++ can describe itself — and generate more. The first compile-time reflection features mark the most transformative turning point in the language's history.
"In June 2025, C++ crossed a Rubicon: it handed us the keys to its own machinery." — Herb Sutter, CppCon 2025 keynote
(2) Memory Safety — recompile and get free improvements
C++26 has important memory safety improvements you get just by recompiling existing code with no changes:
- No more UB for reading uninitialized local variables — this entire category of potential vulnerabilities disappears in C++26
- Hardened standard library — bounds safety for vector, span, string, string_view, and more
Already deployed at Google and Apple across hundreds of millions of lines of C++:
- Fixed over 1,000 bugs at Google
- Projected to prevent 1,000-2,000 bugs per year
- Reduced segfault rate by 30% across the production fleet
- Only ~0.3% average performance overhead
- Across hundreds of millions of lines at Google, only five services opted out entirely
(3) Contracts — pre, post, contract_assert
Language-level contracts: preconditions and postconditions on function declarations, plus a contract assertion statement — infinitely better than C's assert macro.
Final plenary vote: 114 in favor, 12 opposed, 3 abstaining. Contracts are in C++26.
(4) std::execution (Sender/Receiver)
C++'s async model — provides structured concurrency primitives as a standard library feature.
Key Numbers
- 23 active subgroups met in parallel tracks
- 6 parallel tracks throughout the week
- 411 national body comments resolved this meeting
- 24 new guest attendees (first-time visitors)
- Final vote: 114-12-3 (non-unanimous due to contracts concerns)
Sutter's verdict: "The most compelling release since C++11."
Read original → · Saved by Jin · 2026-03-30