std::vector<T,Allocator>::max_size

 

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Deduction guides(C++17)

 

size_type max_size() const;		(until C++11)
size_type max_size() const noexcept;		(since C++11) (until C++20)
constexpr size_type max_size() const noexcept;		(since C++20)

Returns the maximum number of elements the container is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the largest container.

Parameters

(none)

Return value

Maximum number of elements.

Complexity

Constant.

Notes

This value typically reflects the theoretical limit on the size of the container, at most std::numeric_limits<difference_type>::max(). At runtime, the size of the container may be limited to a value smaller than max_size() by the amount of RAM available.

Example

Run this code

#include <iostream>
#include <locale>
#include <vector>
 
int main()
{
    std::vector<char> q;
    std::cout.imbue(std::locale("en_US.UTF-8"));    
    std::cout << "Maximum size of a std::vector is " << q.max_size() << '\n';
}

Possible output:

Maximum size of a std::vector is 9,223,372,036,854,775,807

See also

size	returns the number of elements (public member function)
capacity	returns the number of elements that can be held in currently allocated storage (public member function)