Standard library header <ostream>

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Standard Library header files

Language Support
<cstddef> <limits> <climits> <contract>	<cfloat> <cstdint> <new> <version>	<typeinfo> <exception> <initializer_list>	<csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator> <compare>	<bitset> <tuple> <optional> <any> <variant>	<type_traits> <ratio> <chrono> <typeindex> <functional>	<ctime> <cstdlib>
Strings
<string> <string_view>	<cctype> <cwctype>	<cwchar> <cuchar>	<cstring> <charconv>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<cfenv> <cmath>	<bit>
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>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

This header is part of the Input/output library.

Classes
basic_ostream	wraps a given abstract device (std::basic_streambuf) and provides high-level output interface (class template)
std::ostream	basic_ostream<char> (typedef)
std::wostream	basic_ostream<wchar_t> (typedef)
Functions
operator<<(std::basic_ostream)	inserts character data (function template)
Manipulators
ends	outputs '\0' (function template)
flush	flushes the output stream (function template)
endl	outputs '\n' and flushes the output stream (function template)

Synopsis

namespace std {
    template <class charT, class traits = char_traits<charT> >
        class basic_ostream;
    typedef basic_ostream<char>    ostream;
    typedef basic_ostream<wchar_t> wostream;

    template <class charT, class traits>
        basic_ostream<charT,traits>& endl(basic_ostream<charT,traits>& os);
    template <class charT, class traits>
        basic_ostream<charT,traits>& ends(basic_ostream<charT,traits>& os);
    template <class charT, class traits>
        basic_ostream<charT,traits>& flush(basic_ostream<charT,traits>& os);

    template <class charT, class traits, class T>
        basic_ostream<charT, traits>&
        operator<<(basic_ostream<charT, traits>&& os, const T& x);

    // character inserters
    template<class charT, class traits>
        basic_ostream<charT,traits>& 
        operator<<(basic_ostream<charT,traits>&, charT);
    template<class charT, class traits>
        basic_ostream<charT,traits>& 
        operator<<(basic_ostream<charT,traits>&, char);
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, char);

    // signed and unsigned
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, signed char);
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, unsigned char);
    template<class charT, class traits>
        basic_ostream<charT,traits>& 
        operator<<(basic_ostream<charT,traits>&, const charT*);
    template<class charT, class traits>
        basic_ostream<charT,traits>& 
        operator<<(basic_ostream<charT,traits>&, const char*);
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, const char*);

    // signed and unsigned
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, const signed char*);
    template<class traits>
        basic_ostream<char,traits>& 
        operator<<(basic_ostream<char,traits>&, const unsigned char*);
}

Class std::basic_ostream

template <class charT, class traits = char_traits<charT> >
class basic_ostream : virtual public basic_ios<charT,traits> {
public:
    // types (inherited from basic_ios):
    typedef charT                     char_type;
    typedef typename traits::int_type int_type;
    typedef typename traits::pos_type pos_type;
    typedef typename traits::off_type off_type;
    typedef traits                    traits_type;

    // Constructor/destructor:
    explicit basic_ostream(basic_streambuf<char_type,traits>* sb);
    virtual ~basic_ostream();

    // Prefix/suffix:
    class sentry;

    // Formatted output:
    basic_ostream<charT,traits>& operator<<(
        basic_ostream<charT,traits>& (*pf)(basic_ostream<charT,traits>&));
    basic_ostream<charT,traits>& operator<<(
        basic_ios<charT,traits>& (*pf)(basic_ios<charT,traits>&));
    basic_ostream<charT,traits>& operator<<(
        ios_base& (*pf)(ios_base&));

    basic_ostream<charT,traits>& operator<<(bool n);
    basic_ostream<charT,traits>& operator<<(short n);
    basic_ostream<charT,traits>& operator<<(unsigned short n);
    basic_ostream<charT,traits>& operator<<(int n);
    basic_ostream<charT,traits>& operator<<(unsigned int n);
    basic_ostream<charT,traits>& operator<<(long n);
    basic_ostream<charT,traits>& operator<<(unsigned long n);
    basic_ostream<charT,traits>& operator<<(long long n);
    basic_ostream<charT,traits>& operator<<(unsigned long long n);
    basic_ostream<charT,traits>& operator<<(float f);
    basic_ostream<charT,traits>& operator<<(double f);
    basic_ostream<charT,traits>& operator<<(long double f);

    basic_ostream<charT,traits>& operator<<(const void* p);
    basic_ostream<charT,traits>& operator<<(
        basic_streambuf<char_type,traits>* sb);

    // Unformatted output:
    basic_ostream<charT,traits>& put(char_type c);
    basic_ostream<charT,traits>& write(const char_type* s, streamsize n);

    basic_ostream<charT,traits>& flush();

    // seeks:
    pos_type tellp();
    basic_ostream<charT,traits>& seekp(pos_type);
    basic_ostream<charT,traits>& seekp(off_type, ios_base::seekdir);

protected:
    basic_ostream(const basic_ostream& rhs) = delete;
    basic_ostream(basic_ostream&& rhs);

    // Assign/swap
    basic_ostream& operator=(basic_ostream& rhs) = delete;
    basic_ostream& operator=(const basic_ostream&& rhs);
    void swap(basic_ostream& rhs);
};