[iostream.syn]

# 31 Input/output library [[input.output]](./#input.output)

## 31.4 Standard iostream objects [[iostream.objects]](iostream.objects#iostream.syn)

### 31.4.1 Header <iostream> synopsis [iostream.syn]

[🔗](#header:%3ciostream%3e)

#include <ios> // see [[ios.syn]](ios.syn "31.5.1 Header <ios> synopsis")#include <streambuf> // see [[streambuf.syn]](streambuf.syn "31.6.1 Header <streambuf> synopsis")#include <istream> // see [[istream.syn]](istream.syn "31.7.1 Header <istream> synopsis")#include <ostream> // see [[ostream.syn]](ostream.syn "31.7.2 Header <ostream> synopsis")namespace std {extern istream cin; extern ostream cout; extern ostream cerr; extern ostream clog; extern wistream wcin; extern wostream wcout; extern wostream wcerr; extern wostream wclog;}