C++26 Disapproved: ISO vote fails and stalls the programming language

On October 23, 2026, an unprecedented event occurred in the history of the C++ programming language. ISO National Bodies voted to disapprove the C++26 draft standard during the DIS (Draft International Standard) phase, failing to achieve the required two-thirds majority.

The rejection was primarily driven by concerns over the Contracts feature, which had been in development for years. While the WG21 standardization committee previously approved the draft by a large majority, several National Bodies argued that the feature was not yet ready for release.

• For the first time in C++ history, a DIS ballot has failed to achieve approval.
• The core controversy surrounds the Contracts feature, developed across several years from 2019 to 2024.
• ISO procedures outline multiple options to resolve the deadlock, though all require a majority vote within the committee.
• The unexpected rejection threatens the release timeline of the C++ standard and shakes community trust.

The long road of the Contracts feature

The journey of Contracts began years ago, prominently featured in discussions in Cologne back in 2019 for C++20. After being removed from C++20, a dedicated study group worked extensively from 2020 to 2024 to refine proposals before submitting them to the Evolution Working Group.

In March 2026, WG21 voted to advance the C++26 draft including Contracts to the next phase with a solid majority. However, the subsequent international ISO-level vote accumulated enough dissenting ballots to block the standard's progression.

Potential paths forward and uncertainty

According to ISO rules, the committee faces difficult choices, ranging from submitting a revised draft back to the committee phase to entirely discarding changes and reverting to C++23. Any path chosen will inevitably delay the release of the next standard.

The divide within WG21 highlights deep disagreements where neither side is easily willing to abandon their efforts. This breakdown in consensus threatens the cooperative spirit and trust that has historically guided C++ development.

What this means for developers and the industry

For software engineers and businesses relying on a predictable three-year release cycle, the deadlock creates significant uncertainty. The disruption of C++26 will likely have cascading effects on future standards like C++29.

Resolving the impasse requires rebuilding trust and finding compromise. The upcoming committee meeting in mid-November will be crucial in determining how the C++ community moves past this unprecedented setback.