std::allocator<T>::max_size - cppreference.com

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size_type max_size() const throw();

(until C++11)

size_type max_size() const noexcept;

(since C++11)
(deprecated in C++17)
(removed in C++20)

Returns the maximum theoretically possible value of n, for which the call allocate(n, 0) could succeed.

In most implementations, this returns std::numeric_limits<size_type>::max() / sizeof(value_type).

Parameters

(none)

Return value

The maximum supported allocation size.

See also

returns the maximum object size supported by the allocator
(public static member function of std::allocator_traits<Alloc>) [edit]