std::string_view max_size() method

since C++17

// Const version only
constexpr bool max_size() const noexcept;

Returns the maximum number of characters the view is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the largest container.

Parameters

(none)

Return value

Maximum number of characters the view can hold.

Complexity

Constant - O(1).

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

Main.cpp

#include <iostream>
#include <limits>
#include <string_view>
 
int main() {
    std::cout
        << std::numeric_limits<std::int64_t>::max()
        << " <- numeric_limits<int64_t>::max()\n"
        << std::string_view{}.max_size()
        << " <- std::string_view::max_size()\n"
        << std::basic_string_view<char>{}.max_size()
        << " <- std::basic_string_view<char>::max_size()\n"
        << std::basic_string_view<char16_t>{}.max_size()
        << " <- std::basic_string_view<char16_t>::max_size()\n"
        << std::wstring_view{}.max_size()
        << " <- std::wstring_view::max_size()\n"
        << std::basic_string_view<char32_t>{}.max_size()
        << " <- std::basic_string_view<char32_t>::max_size()\n"
        ;
}

Possible output

9223372036854775807 <- numeric_limits<int64_t>::max()
4611686018427387899 <- std::string_view::max_size()
4611686018427387899 <- std::basic_string_view<char>::max_size()
2305843009213693949 <- std::basic_string_view<char16_t>::max_size()
1152921504606846974 <- std::wstring_view::max_size()
1152921504606846974 <- std::basic_string_view<char32_t>::max_size()