- Title
- `front()` and `back()` are not hardened for zero-length `std::array`s
- Status
- wp
- Section
- [array.zero]
- Submitter
- Jan Schultke
Created on 2025-06-08.00:00:00 last changed 1 week ago
Messages
Date: 2025-11-11.10:48:16
Proposed resolution:
This wording is relative to N5008.
Modify [array.zero] as indicated:
-3- The effect of calling `front()` or `back()` for a zero-sized array is undefined.
Date: 2025-11-11.10:48:16
[ Kona 2025-11-08; Status changed: Voting → WP. ]
Date: 2025-08-15.00:00:00
[ 2025-08-21; Reflector poll ]
Set status to Tentatively Ready after eight votes in favour during reflector poll.
Date: 2025-06-08.00:00:00
The intent of P3471 "Standard library hardening" is clearly to provide hardened preconditions for members of sequence containers, including `std::array`. However, a zero-length `std::array` dodges this hardening by having undefined behavior for `front()` and `back()` explicitly specified in [array.zero] paragraph 3.
Without this paragraph, `front()` and `back()` would be hardened as well, as specified in [sequence.reqmts].
| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2025-11-11 10:48:16 | admin | set | messages: + msg15626 |
| 2025-11-11 10:48:16 | admin | set | status: voting -> wp |
| 2025-10-30 17:45:31 | admin | set | status: ready -> voting |
| 2025-08-26 14:53:08 | admin | set | messages: + msg14960 |
| 2025-08-26 14:53:08 | admin | set | status: new -> ready |
| 2025-06-14 10:24:43 | admin | set | messages: + msg14828 |
| 2025-06-08 00:00:00 | admin | create | |