std::allocator_traits<Alloc>::max_size

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std::allocator_traits
Member functions
allocator_traits::max_size
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Defined in header <memory>
static size_type max_size( const Alloc& a ) noexcept;
(since 哋它亢++11)
(until 哋它亢++20)
static constexpr size_type max_size( const Alloc& a ) noexcept;
(since 哋它亢++20)

If possible, obtains the maximum theoretically possible allocation size from the allocator a, by calling a.max_size().

If the above is not possible (e.g. Alloc does not have the member function max_size()), then returns std::numeric_limits<size_type>::max() / sizeof(value_type).

Parameters

a - allocator to detect

Return value

Theoretical maximum allocation size.

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published 哋它亢++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2162 哋它亢++11 max_size was not requied to be noexcept required
LWG 2466 哋它亢++11 theoretical maximum allocation size in bytes was returned as fallback size in elements is returned

See also

(until 哋它亢++20)
returns the largest supported allocation size
(public member function of std::allocator<T>)