std::basic_string<CharT,Traits,Allocator>::operator basic_string_view

 

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

Search basic_string::find basic_string::rfind basic_string::find_first_of basic_string::find_first_not_of basic_string::find_last_of basic_string::find_last_not_of Constants basic_string::npos Deduction guides (C++17) Non-member functions operator+ swap(std::basic_string) operator""s (C++14) erase(std::basic_string)erase_if(std::basic_string) (C++20)(C++20) I/O operator<<operator>> getline Comparison operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) Numeric conversion stoistolstoll (C++11)(C++11)(C++11) stoulstoull (C++11)(C++11) stofstodstold (C++11)(C++11)(C++11) to_string (C++11) to_wstring (C++11) Helper classes hash<std::string>hash<std::wstring>hash<std::u32string>hash<std::u16string>hash<std::u8string> (C++11)  (C++11)(C++11)(C++11)(C++20) hash<std::pmr::string>hash<std::pmr::wstring>hash<std::pmr::u32string>hash<std::pmr::u16string>hash<std::pmr::u8string> (C++17)(C++17)(C++17)(C++17)(C++20)

 

operator std::basic_string_view<CharT, Traits>() const noexcept;		(since C++17) (until C++20)
constexpr operator std::basic_string_view<CharT, Traits>() const noexcept;		(since C++20)

Returns a std::basic_string_view, constructed as if by std::basic_string_view<CharT, Traits>(data(), size())

Parameters

(none)

Return value

A string view representing the entire contents of the string.

Notes

It is the programmer's responsibility to ensure that the resulting string view does not outlive the string.

std::string get_string();
int f(std::string_view sv);
 
int x = f(get_string()); // OK
std::string_view sv = get_string(); // Bad: holds a dangling pointer

Example

Run this code

#include <iostream>
#include <string>
#include <string_view>
 
void show_wstring_size(std::wstring_view wcstr_v)
{
  std::cout << wcstr_v.size() << " code points\n";
}
 
int main()
{
  std::string cppstr = "ラーメン";   // narrow string
  std::wstring wcstr = L"ラーメン";  // wide string
 
  // Implicit conversion from string to string_view
  // via std::string::operator string_view:
  std::string_view cppstr_v = cppstr;
 
  std::cout << cppstr_v << '\n'
            << cppstr_v.size() << " code units\n";
 
  // Implicit conversion from wstring to wstring_view
  // via std::wstring::operator wstring_view:
  show_wstring_size(wcstr);
}

Output:

ラーメン
12 code units
4 code points

See also

(constructor) (C++17)

constructs a basic_string_view (public member function of std::basic_string_view<CharT,Traits>)