std::map<Key,T,Compare,Allocator>::max_size

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.

# Declarations

size_type max_size() const;

(noexcept since C++11)

# Return value

Maximum number of elements.

# 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 <locale>
#include <map>
 
int main()
{
    std::map<char, char> p;
    std::map<long, char> q;
 
    std::cout.imbue(std::locale("en_US.UTF-8"));
    std::cout << std::uppercase
              << "p.max_size() = " << std::dec << p.max_size() << " = 0x"
              << std::hex << p.max_size() << '\n'
              << "q.max_size() = " << std::dec << q.max_size() << " = 0x"
              << std::hex << q.max_size() << '\n';
}

# See also

• size