Breaking: ISO C++ Committee officially shipped C++26 on March 28, 2026 at the London (Croydon) meeting. This is the latest revision of the C++ programming language, following C++23 (ISO/IEC 14882:2024). The new standard brings compile-time reflection, contracts, a parallel scheduler, and major standard library additions.

Compile-Time Reflection

C++26 introduces compile-time reflection using the new ^^ operator (colloquially called the "cat-ears operator"). This replaces the earlier reflexpr keyword from the Reflection TS. The new <meta> header provides library support for inspecting and generating code at compile time. Experimental implementations are available in GCC 16 and a Clang fork by Dan Katz.

Contracts

Design-by-contract support lands via the new <contracts> header. The contract_assert keyword enables runtime contract checking, while pre and post become identifiers with special meaning for specifying function preconditions and postconditions.

Parallel Scheduler and Execution Control

A new parallel scheduler in <execution> provides a standard async execution context that guarantees forward progress. The "execution control library" adds support for asynchronous operations and coroutines, including a std::execution::task class for managing concurrent work.

Key Standard Library Additions

• std::copyable_function — A general-purpose polymorphic function wrapper that supports copy construction and assignment
• std::is_within_lifetime — Determines if a pointer points to an object within its lifetime
• std::submdspan() — Returns a view of a subset of an existing std::mdspan
• std::formatter<std::filesystem::path> — Specialization for formatting filesystem paths
• std::views::concat — A view for concatenating other views together
• std::ranges::generate_random — Fills a range with random numbers from a uniform random bit generator
• std::println() improvements — Printing blank lines with std::println() (already implemented in C++23 by most compilers)
• Interfacing string streams and std::bitset with std::string_view

Deprecations and Removals

• Deprecated std::memory_order::consume and std::kill_dependency() due to low compiler adoption and complexity
• Removed the [[carries_dependency]] attribute due to the deprecation of memory_order::consume

Compiler Support

GCC 16.1 (released May 8, 2026) supports most C++26 features including contracts, reflection, and the new standard library additions. Clang is progressively implementing reflection through experimental forks. EDG also provides a reflection implementation. Developers can test features on Compiler Explorer (godbolt.org).

Source: Wikipedia — C++26