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

 

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std::vector

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vector::vector vector::~vector vector::operator= vector::assign vector::assign_range (C++23)   vector::get_allocator Element access vector::operator[] vector::at vector::data vector::front vector::back Iterators vector::beginvector::cbegin (C++11) vector::endvector::cend (C++11) vector::rbeginvector::crbegin (C++11) vector::rendvector::crend (C++11)	Capacity vector::empty vector::size vector::max_size vector::reserve vector::capacity vector::shrink_to_fit (DR*) Modifiers vector::clear vector::erase vector::insert vector::insert_range (C++23) vector::append_range (C++23) vector::emplace (C++11) vector::emplace_back (C++11) vector::push_back vector::pop_back vector::resize vector::swap
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operator==operator<=> (C++20) swap(std::vector) erase(std::vector)erase_if(std::vector) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides(C++17)

 

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

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> p;std::vector<long> 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';}

Possible output:

p.max_size() = 9,223,372,036,854,775,807 = 0x7,FFF,FFF,FFF,FFF,FFF q.max_size() = 1,152,921,504,606,846,975 = 0xFFF,FFF,FFF,FFF,FFF

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)