HN: C++26 Approved — Reflection, Memory Safety, Contracts

The ISO C++ committee has officially completed technical work on C++26 at the London Croydon meeting, with a 114-12 vote in favor. This is being called the most impactful release since C++11.

The “Fab Four” headline features:

1. Reflection: The biggest upgrade since templates. For the first time, C++ can describe itself and generate code at compile-time. Sutter called it “C++‘s decade-defining rocket engine.” This enables metaprogramming capabilities that previously required external code generation.

2. Memory safety improvements: Just by recompiling as C++26, you get:

   • No more UB for reading uninitialized local variables
   • Hardened standard library with bounds checking for vector, span, string, string_view

   Google deployed these checks across hundreds of millions of lines of code with only 0.3% average performance overhead—and fixed over 1,000 bugs while reducing segfault rates by 30%.

3. Contracts: Preconditions, postconditions, and contract_assert provide formal specification of function behavior. The feature passed despite sustained technical concerns from committee members (100-14 vote).

4. std::execution: A unified framework for concurrency and parallelism with structured concurrency guarantees that enable data-race-free code by construction.

Why adoption will be fast:

Unlike C++17/20/23 where major features were adopted gradually, C++26’s feature set addresses daily developer pain points. Reflection alone eliminates years of boilerplate. Memory safety improvements work automatically on recompilation.

Context: 210 attendees from 24 nations participated, with 130 in-person and 80 remote. The standard now enters the final ISO approval ballot process.

Source: herbsutter.com