public member function
<vector>

std::vector::max_size

size_type max_size() const;

size_type max_size() const noexcept;
Return maximum size
Returns the maximum number of elements that the vector can hold.

This is the maximum potential size the container can reach due to known system or library implementation limitations, but the container is by no means guaranteed to be able to reach that size: it can still fail to allocate storage at any point before that size is reached.

Parameters

none

Return Value

The maximum number of elements a vector container can hold as content.

Member type size_type is an unsigned integral type.

Example

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// comparing size, capacity and max_size
#include <iostream>
#include <vector>

int main ()
{
  std::vector<int> myvector;

  // set some content in the vector:
  for (int i=0; i<100; i++) myvector.push_back(i);

  std::cout << "size: " << myvector.size() << "\n";
  std::cout << "capacity: " << myvector.capacity() << "\n";
  std::cout << "max_size: " << myvector.max_size() << "\n";
  return 0;
}


A possible output for this program could be:
size: 100
capacity: 128
max_size: 1073741823

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No contained elements are accessed: concurrently accessing or modifying them is safe.

Exception safety

No-throw guarantee: this member function never throws exceptions.

See also

vector::capacity
Return size of allocated storage capacity (public member function )
vector::size
Return size (public member function )
vector::resize
Change size (public member function )

C++