std::basic_string<CharT,Traits,Allocator>::max_size

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string

Member functions basic_string::basic_string basic_string::operator= basic_string::assign basic_string::get_allocator Element access basic_string::at basic_string::operator[] basic_string::front (C++11) basic_string::back (C++11) basic_string::data basic_string::c_str basic_string::operator  basic_string_view (C++17) Iterators basic_string::beginbasic_string::cbegin (C++11) basic_string::endbasic_string::cend (C++11) basic_string::rbeginbasic_string::crbegin (C++11) basic_string::rendbasic_string::crend (C++11) Capacity basic_string::empty basic_string::sizebasic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (C++11)   Operations basic_string::clear basic_string::insert basic_string::erase basic_string::push_back basic_string::pop_back (C++11) basic_string::append basic_string::operator+= basic_string::compare basic_string::starts_with (C++20)   basic_string::ends_with (C++20) basic_string::contains (C++23) basic_string::replace basic_string::substr basic_string::copy basic_string::resize basic_string::resize_and_overwrite (C++23) basic_string::swap

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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 string is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the largest string.

Parameters

(none)

Return value

Maximum number of characters.

Complexity

Constant.

Example

Run this code

#include <iostream>
#include <string>
#include <climits>
 
int main()
{
    std::string s;
    std::cout
        << "Maximum size of a string is " << s.max_size() << " ("
        << std::hex << std::showbase << s.max_size()
        << "), pointer size: " << std::dec
        << CHAR_BIT*sizeof(void*) << " bits\n";
}

Possible output:

Maximum size of a string is 9223372036854775807 (0x7fffffffffffffff), pointer size: 64 bits

See also

sizelength	returns the number of characters (public member function)
max_size (C++17)	returns the maximum number of characters (public member function of std::basic_string_view<CharT,Traits>)