Standard library header <istream>

 

C++

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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 input/output library.

Classes
basic_istream	wraps a given abstract device (std::basic_streambuf) and provides high-level input interface (class template)
std::istream	std::basic_istream<char> (typedef)
std::wistream	std::basic_istream<wchar_t> (typedef)
basic_iostream	wraps a given abstract device (std::basic_streambuf) and provides high-level input/output interface (class template)
std::iostream	std::basic_iostream<char> (typedef)
std::wiostream	std::basic_iostream<wchar_t> (typedef)
Functions
operator>>(std::basic_istream)	extracts characters and character arrays (function template)
Manipulators
ws	consumes whitespace (function template)

Synopsis

namespace std {template<class CharT, class Traits = char_traits<CharT>>class basic_istream;   using istream = basic_istream<char>;using wistream = basic_istream<wchar_t>;   template<class CharT, class Traits = char_traits<CharT>>class basic_iostream;   using iostream = basic_iostream<char>;using wiostream = basic_iostream<wchar_t>;   template<class CharT, class Traits> basic_istream<CharT, Traits>& ws(basic_istream<CharT, Traits>& is);   template<class Istream, class T> Istream&& operator>>(Istream&& is, T&& x);}

Class template std::basic_istream

namespace std {template<class CharT, class Traits = char_traits<CharT>>class basic_istream :virtualpublic basic_ios<CharT, Traits>{public:// types (inherited from basic_ios)using char_type = CharT;using int_type =typename Traits::int_type;using pos_type =typename Traits::pos_type;using off_type =typename Traits::off_type;using traits_type = Traits;   // constructor/destructorexplicit basic_istream(basic_streambuf<CharT, Traits>* sb);virtual ~basic_istream();   // prefix/suffixclass sentry;   // formatted input basic_istream<CharT, Traits>& operator>>(basic_istream<CharT, Traits>&(*pf)(basic_istream<CharT, Traits>&)); basic_istream<CharT, Traits>& operator>>(basic_ios<CharT, Traits>&(*pf)(basic_ios<CharT, Traits>&)); basic_istream<CharT, Traits>& operator>>(ios_base&(*pf)(ios_base&));   basic_istream<CharT, Traits>& operator>>(bool& n); basic_istream<CharT, Traits>& operator>>(short& n); basic_istream<CharT, Traits>& operator>>(unsignedshort& n); basic_istream<CharT, Traits>& operator>>(int& n); basic_istream<CharT, Traits>& operator>>(unsignedint& n); basic_istream<CharT, Traits>& operator>>(long& n); basic_istream<CharT, Traits>& operator>>(unsignedlong& n); basic_istream<CharT, Traits>& operator>>(longlong& n); basic_istream<CharT, Traits>& operator>>(unsignedlonglong& n); basic_istream<CharT, Traits>& operator>>(float& f); basic_istream<CharT, Traits>& operator>>(double& f); basic_istream<CharT, Traits>& operator>>(longdouble& f);   basic_istream<CharT, Traits>& operator>>(void*& p); basic_istream<CharT, Traits>& operator>>(basic_streambuf<char_type, Traits>* sb);   // unformatted input streamsize gcount()const; int_type get(); basic_istream<CharT, Traits>& get(char_type& c); basic_istream<CharT, Traits>& get(char_type* s, streamsize n); basic_istream<CharT, Traits>& get(char_type* s, streamsize n, char_type delim); basic_istream<CharT, Traits>& get(basic_streambuf<char_type, Traits>& sb); basic_istream<CharT, Traits>& get(basic_streambuf<char_type, Traits>& sb, char_type delim);   basic_istream<CharT, Traits>& getline(char_type* s, streamsize n); basic_istream<CharT, Traits>& getline(char_type* s, streamsize n, char_type delim);   basic_istream<CharT, Traits>& ignore(streamsize n =1, int_type delim = Traits::eof()); int_type peek(); basic_istream<CharT, Traits>& read (char_type* s, streamsize n); streamsize readsome(char_type* s, streamsize n);   basic_istream<CharT, Traits>& putback(char_type c); basic_istream<CharT, Traits>& unget();int sync();   pos_type tellg(); basic_istream<CharT, Traits>& seekg(pos_type); basic_istream<CharT, Traits>& seekg(off_type, ios_base::seekdir);   protected:// copy/move constructor basic_istream(const basic_istream&)= delete; basic_istream(basic_istream&& rhs);   // assign and swap basic_istream& operator=(const basic_istream&)= delete; basic_istream& operator=(basic_istream&& rhs);void swap(basic_istream& rhs);};   // character extraction templatestemplate<class CharT, class Traits> basic_istream<CharT, Traits>& operator>>(basic_istream<CharT, Traits>&, CharT&);template<class Traits> basic_istream<char, Traits>& operator>>(basic_istream<char, Traits>&, unsignedchar&);template<class Traits> basic_istream<char, Traits>& operator>>(basic_istream<char, Traits>&, signedchar&);   template<class CharT, class Traits, size_t N> basic_istream<CharT, Traits>& operator>>(basic_istream<CharT, Traits>&, CharT(&)[N]);template<class Traits, size_t N> basic_istream<char, Traits>& operator>>(basic_istream<char, Traits>&, unsignedchar(&)[N]);template<class Traits, size_t N> basic_istream<char, Traits>& operator>>(basic_istream<char, Traits>&, signedchar(&)[N]);}

Class std::basic_istream::sentry

namespace std {template<class CharT, class Traits = char_traits<CharT>>class basic_istream<CharT, Traits>::sentry{bool ok_;// exposition onlypublic:explicit sentry(basic_istream<CharT, Traits>& is, bool noskipws =false); ~sentry();explicit operator bool()const{return ok_;} sentry(const sentry&)= delete; sentry& operator=(const sentry&)= delete;};}

Class template std::basic_iostream

namespace std {template<class CharT, class Traits = char_traits<CharT>>class basic_iostream :public basic_istream<CharT, Traits>, public basic_ostream<CharT, Traits>{public:using char_type = CharT;using int_type =typename Traits::int_type;using pos_type =typename Traits::pos_type;using off_type =typename Traits::off_type;using traits_type = Traits;   // constructorexplicit basic_iostream(basic_streambuf<CharT, Traits>* sb);   // destructorvirtual ~basic_iostream();   protected:// constructor basic_iostream(const basic_iostream&)= delete; basic_iostream(basic_iostream&& rhs);   // assign and swap basic_iostream& operator=(const basic_iostream&)= delete; basic_iostream& operator=(basic_iostream&& rhs);void swap(basic_iostream& rhs);};}