National Body representatives cast their votes on the C++26 draft, resulting in a disapproval on October 23, 2026.
C++26 DIS APPROVAL FAILS, CONTRACTS BLOCK STANDARD
*On October 23, 2026 the ISO National Bodies rejected the C++26 draft. The vote marks the first DIS failure in C++ history and throws the language’s release schedule into uncertainty.*
On October 23, 2026 the ISO National Bodies cast their votes on the C++26 draft. The result, announced by committee member Andreas Fertig, was a clear “Disapproved”. This marks the first time a DIS (Draft International Standard) has failed for C++ since the voting process began in 1998. The failure hinges on the Contracts feature, which a number of NBs deem insufficiently mature for inclusion.
The vote follows a long‑running debate. Contracts were first floated in the C++20 discussions, removed, refined by a study group from 2020 to 2024, and re‑introduced in the C++26 draft. WG21 approved the draft in March 2026 with a strong majority, but the final DIS stage exposed a split among the national representatives. The outcome threatens to delay the next language release, jeopardize training schedules for 2027, and force the committee to choose a new path forward.
Why did the C++26 DIS vote fail?
The twelve‑week DIS ballot closed on October 23, 2026 with a “Disapproved” result. ISO rules require a two‑thirds majority of National Bodies; that threshold was not met. Comments from the NBs singled out the Contracts feature as the sticking point, arguing it is not yet ready for release. The dissent was not based on new technical data, according to committee member Andreas Fertig, but on the perception that the feature remains immature. This is the first time a C++ DIS has been rejected since the process began in 1998.
What does the DIS failure mean for the C++ roadmap?
A failed DIS stalls the progression to a final International Standard. ISO can submit a revised draft for a new DIS, move the draft to the Committee Draft (CD) phase, publish it as a Technical Specification, or cancel the project altogether. Any of these paths delays the next official release and puts the name C++26 in doubt. The delay ripples through industry training plans, toolchain roadmaps, and the timing of future standards such as C++29.
How have contracts shaped the C++26 saga?
Contracts have been on the C++ wish list since at least 2019, when they were briefly included in the C++20 draft before being removed at the same meeting. A dedicated study group worked on contracts from 2020 to roughly 2024, feeding proposals to the Evolution Working Group. In March 2026 WG21 voted the C++26 draft—including Contracts—into the DIS stage with a large majority, though dissenting votes were recorded. The DIS rejection shows that, despite prior approvals, the Contracts feature remains the decisive fault line.
What are the next steps for WG21 and ISO?
WG21 must now decide which of ISO’s four options to pursue. All require a fresh majority within the working group, which previously backed C++26 with Contracts by more than two‑thirds. Removing C++26 would revert the language to C++23 and push all pending features into C++29, a move that would discard years of work. Conversely, a revised draft could address NB concerns and re‑enter the DIS ballot, preserving the C++26 timeline. The committee’s choice will shape the language’s evolution for the next decade.
Frequently asked questions
Did any previous DIS fail for C++?
Only one prior DIS failed: ISO/IEC DIS 26926 C++/CLI Language Specification dated August 11, 2006, which was halted.
What majority is required for a DIS to pass?
A two‑thirds majority of the ISO National Bodies is required for a DIS to be approved.
What options does ISO have after a DIS failure?
ISO can submit a revised draft for a new DIS vote, move the draft to the CD phase, publish it as a Technical Specification, or cancel the project.
The C++ community now watches WG21’s next move. Whether the committee revises the draft, pushes it as a Technical Specification, or abandons the current trajectory, the decision will reverberate through compilers, libraries, and enterprise codebases. A renewed vote could restore momentum, but the Contracts controversy ensures that any path forward will be contested. The stakes are high: the language’s credibility and its roadmap to C++29 hang in the balance.
Sources: Hacker News article "C++26 Disapproved" by Andreas Fertig, https://andreasfertig.com/blog/2026/11/cpp26-dis-failed-how-does-cpp-survive/