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Section: 16.4.4.6 [allocator.requirements] Status: C++17 Submitter: Daniel Krügler Opened: 2015-03-22 Last modified: 2017-07-30
Priority: Not Prioritized
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Discussion:
This issue is a spin-off of issue LWG 2447: It focuses on the observation that 16.4.4.6 [allocator.requirements] p9 (based on the numbering of working draft N4296) gives the template member construct more relaxations than the template member destroy:
An allocator may constrain the types on which it can be instantiated and the arguments for which its construct member may be called. If a type cannot be used with a particular allocator, the allocator class or the call to construct may fail to instantiate.
Construction and destruction of a type T are usually intimately related to each other, so it seems similarly useful to allow the destroy member to fail to instantiate for a possible sub-set of instantiation types.
[2015-04-01 Library reflector vote]
The issue has been identified as Tentatively Ready based on six votes in favour.
Proposed resolution:
This wording is relative to N4296.
Change 16.4.4.6 [allocator.requirements] p9 as indicated:
-8- An allocator may constrain the types on which it can be instantiated and the arguments for which its construct or destroy members may be called. If a type cannot be used with a particular allocator, the allocator class or the call to construct or destroy may fail to instantiate.