Standard library header <string_view>

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library(C++20)

Diagnostics library

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)

Atomic operations library(C++11)

Thread support library(C++11)

Technical Specifications

 

Standard Library headers

Language Support
<cstddef> <cstdlib> <version> <limits> <climits>	<cfloat> <cstdint> <new> <typeinfo>	<source_location> <exception> <initializer_list> <compare>	<coroutine> <csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator>	<bitset> <tuple> <optional> <any>	<variant> <type_traits> <ratio> <chrono>	<typeindex> <functional> <ctime>
Strings
<string> <string_view> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Ranges
<ranges>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<cfenv> <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
Regular expressions
<regex>
Filesystem support
<filesystem>
Thread support
<thread> <atomic> <mutex>	<shared_mutex> <condition_variable> <future>	<stop_token> <semaphore>	<latch> <barrier>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

This header is part of the strings library.

Includes
<compare> (C++20)	Three-way comparison operator support
Classes
basic_string_view (C++17)	read-only string view (class template)
std::string_view(C++17)	std::basic_string_view<char>
std::u8string_view(C++20)	std::basic_string_view<char8_t>
std::u16string_view(C++17)	std::basic_string_view<char16_t>
std::u32string_view(C++17)	std::basic_string_view<char32_t>
std::wstring_view(C++17)	std::basic_string_view<wchar_t>
std::hash<std::string_view>std::hash<std::wstring_view>std::hash<std::u8string_view>std::hash<std::u16string_view>std::hash<std::u32string_view> (C++17)(C++17)(C++20)(C++17)(C++17)	hash support for string views (class template specialization)
Forward declarations
Defined in header <functional>
hash (C++11)	hash function object (class template)
Functions
operator==operator!=operator<operator>operator<=operator>=operator<=> (removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)	lexicographically compares two string views (function template)
operator<<	performs stream output on string views (function template)
swap	swaps the values of two objects (function template)
Range access
begincbegin (C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)
endcend (C++11)(C++14)	returns an iterator to the end of a container or array (function template)
rbegincrbegin (C++14)	returns a reverse iterator to a container or array (function template)
rendcrend (C++14)	returns a reverse end iterator for a container or array (function template)
sizessize (C++17)(C++20)	returns the size of a container or array (function template)
empty (C++17)	checks whether the container is empty (function template)
data (C++17)	obtains the pointer to the underlying array (function template)
Literals
Defined in inline namespace std::literals::string_view_literals
operator""sv (C++17)	Creates a string view of a character array literal (function)

Synopsis

#include <compare>   namespace std {// class template basic_­string_­viewtemplate<class CharT, class Traits = char_traits<CharT>>class basic_string_view;   template<class CharT, class Traits>inlineconstexprbool ranges::enable_view<basic_string_view<CharT, Traits>>=true;template<class CharT, class Traits>inlineconstexprbool ranges::enable_borrowed_range<basic_string_view<CharT, Traits>>=true;   // non-member comparison functionstemplate<class CharT, class Traits>constexprbool operator==(basic_string_view<CharT, Traits> x, basic_string_view<CharT, Traits> y)noexcept;template<class CharT, class Traits>constexpr/* see description */ operator<=>(basic_string_view<CharT, Traits> x, basic_string_view<CharT, Traits> y)noexcept;   // sufficient additional overloads of comparison functions   // inserters and extractorstemplate<class CharT, class Traits> basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>& os, basic_string_view<CharT, Traits> str);   // basic_­string_­view typedef namesusing string_view = basic_string_view<char>;using u8string_view = basic_string_view<char8_t>;using u16string_view = basic_string_view<char16_t>;using u32string_view = basic_string_view<char32_t>;using wstring_view = basic_string_view<wchar_t>;   // hash supporttemplate<class T>struct hash;template<>struct hash<string_view>;template<>struct hash<u8string_view>;template<>struct hash<u16string_view>;template<>struct hash<u32string_view>;template<>struct hash<wstring_view>;   inlinenamespace literals {inlinenamespace string_view_literals {// suffix for basic_­string_­view literalsconstexpr string_view operator""sv(constchar* str, size_t len)noexcept;constexpr u8string_view operator""sv(const char8_t* str, size_t len)noexcept;constexpr u16string_view operator""sv(constchar16_t* str, size_t len)noexcept;constexpr u32string_view operator""sv(constchar32_t* str, size_t len)noexcept;constexpr wstring_view operator""sv(constwchar_t* str, size_t len)noexcept;}}}

Class template std::basic_string_view

namespace std {template<class CharT, class Traits = char_traits<CharT>>class basic_string_view {public:// typesusing Traits_type = Traits;using value_type = CharT;using pointer = value_type*;using const_pointer =const value_type*;using reference = value_type&;using const_reference =const value_type&;using const_iterator =/* implementation-defined */using iterator = const_iterator;using const_reverse_iterator = reverse_iterator<const_iterator>;using reverse_iterator = const_reverse_iterator;using size_type = size_t;using difference_type = ptrdiff_t;staticconstexpr size_type npos = size_type(-1);   // construction and assignmentconstexpr basic_string_view()noexcept;constexpr basic_string_view(const basic_string_view&)noexcept=default;constexpr basic_string_view& operator=(const basic_string_view&)noexcept=default;constexpr basic_string_view(const CharT* str);constexpr basic_string_view(const CharT* str, size_type len);template<class It, class End>constexpr basic_string_view(It begin, End end);   // iterator supportconstexpr const_iterator begin()constnoexcept;constexpr const_iterator end()constnoexcept;constexpr const_iterator cbegin()constnoexcept;constexpr const_iterator cend()constnoexcept;constexpr const_reverse_iterator rbegin()constnoexcept;constexpr const_reverse_iterator rend()constnoexcept;constexpr const_reverse_iterator crbegin()constnoexcept;constexpr const_reverse_iterator crend()constnoexcept;   // capacityconstexpr size_type size()constnoexcept;constexpr size_type length()constnoexcept;constexpr size_type max_size()constnoexcept;[[nodiscard]]constexprbool empty()constnoexcept;   // element accessconstexpr const_reference operator[](size_type pos)const;constexpr const_reference at(size_type pos)const;constexpr const_reference front()const;constexpr const_reference back()const;constexpr const_pointer data()constnoexcept;   // modifiersconstexprvoid remove_prefix(size_type n);constexprvoid remove_suffix(size_type n);constexprvoid swap(basic_string_view& s)noexcept;   // string operationsconstexpr size_type copy(CharT* s, size_type n, size_type pos =0)const;   constexpr basic_string_view substr(size_type pos =0, size_type n = npos)const;   constexprint compare(basic_string_view s)constnoexcept;constexprint compare(size_type pos1, size_type n1, basic_string_view s)const;constexprint compare(size_type pos1, size_type n1, basic_string_view s, size_type pos2, size_type n2)const;constexprint compare(const CharT* s)const;constexprint compare(size_type pos1, size_type n1, const CharT* s)const;constexprint compare(size_type pos1, size_type n1, const CharT* s, size_type n2)const;   constexprbool starts_with(basic_string_view x)constnoexcept;constexprbool starts_with(CharT x)constnoexcept;constexprbool starts_with(const CharT* x)const;constexprbool ends_with(basic_string_view x)constnoexcept;constexprbool ends_with(CharT x)constnoexcept;constexprbool ends_with(const CharT* x)const;   // searchingconstexpr size_type find(basic_string_view s, size_type pos =0)constnoexcept;constexpr size_type find(CharT c, size_type pos =0)constnoexcept;constexpr size_type find(const CharT* s, size_type pos, size_type n)const;constexpr size_type find(const CharT* s, size_type pos =0)const;constexpr size_type rfind(basic_string_view s, size_type pos = npos)constnoexcept;constexpr size_type rfind(CharT c, size_type pos = npos)constnoexcept;constexpr size_type rfind(const CharT* s, size_type pos, size_type n)const;constexpr size_type rfind(const CharT* s, size_type pos = npos)const;   constexpr size_type find_first_of(basic_string_view s, size_type pos =0)constnoexcept;constexpr size_type find_first_of(CharT c, size_type pos =0)constnoexcept;constexpr size_type find_first_of(const CharT* s, size_type pos, size_type n)const;constexpr size_type find_first_of(const CharT* s, size_type pos =0)const;constexpr size_type find_last_of(basic_string_view s, size_type pos = npos)constnoexcept;constexpr size_type find_last_of(CharT c, size_type pos = npos)constnoexcept;constexpr size_type find_last_of(const CharT* s, size_type pos, size_type n)const;constexpr size_type find_last_of(const CharT* s, size_type pos = npos)const;constexpr size_type find_first_not_of(basic_string_view s, size_type pos =0)constnoexcept;constexpr size_type find_first_not_of(CharT c, size_type pos =0)constnoexcept;constexpr size_type find_first_not_of(const CharT* s, size_type pos, size_type n)const;constexpr size_type find_first_not_of(const CharT* s, size_type pos =0)const;constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos)constnoexcept;constexpr size_type find_last_not_of(CharT c, size_type pos = npos)constnoexcept;constexpr size_type find_last_not_of(const CharT* s, size_type pos, size_type n)const;constexpr size_type find_last_not_of(const CharT* s, size_type pos = npos)const;   private: const_pointer data_;// exposition only size_type size_;// exposition only};   // deduction guidetemplate<class It, class End> basic_string_view(It, End)-> basic_string_view<iter_value_t<It>>;}