std::allocator_arg_t
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Defined in header
<memory> |
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struct allocator_arg_t { explicit allocator_arg_t() = default; };
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(since C++11) | |
std::allocator_arg_t is an empty class type used to disambiguate the overloads of constructors and member functions of allocator-aware objects, including std::tuple, std::function, std::packaged_task, (until C++17)and std::promise.
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2510 | C++11 | the default constructor was non-explicit, which could lead to ambiguity | made explicit |
See also
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(C++11)
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an object of type std::allocator_arg_t used to select allocator-aware constructors (constant) |
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(C++11)
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checks if the specified type supports uses-allocator construction (class template) |