std::flat_set<Key,Compare,KeyContainer>::max_size - cppreference.com

size_type max_size() const noexcept;

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.

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

#include <iostream>
#include <flat_set>
#include <locale>

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

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

See also