<iosfwd>

Library:  Input/output

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The header <iosfwd> is part of the Input/output library of the C++ Standard Library. It declares all essential iostream class templates and defines aliases for specializations of these templates on types char and wchar_t.

#include <iosfwd>

namespace std {
  // forward declare the traits class
  template<class charT> struct char_traits;

  // forward declare the positioning class
  template<class stateT> class fpos;

  // forward declare the state class
  class mbstate_t;

  // forward declare the allocator class
  template<class T> class allocator;

  // forward declare the iostreams class templates
  template<class charT,class traits=char_traits<charT> > 
  class basic_ios;

  template<class charT,class traits=char_traits<charT> > 
  class basic_streambuf;

  template<class charT,class traits=char_traits<charT> > 
  class basic_istream;

  template<class charT,class traits=char_traits<charT> > 
  class basic_ostream;

  template<class charT,class traits=char_traits<charT>,
           class Allocator = allocator<charT> >
  class basic_stringbuf;

  template<class charT,class traits=char_traits<charT>,
           class Allocator = allocator<charT> > 
  class basic_istringstream;

  template<class charT,class traits=char_traits<charT>,
           class Allocator = allocator<charT> >
  class basic_ostringstream;

  template<class charT,class traits=char_traits<charT> > 
  class basic_filebuf;

  template<class charT,class traits=char_traits<charT> > 
  class basic_ifstream;

  template<class charT,class traits=char_traits<charT> > 
  class basic_ofstream;

  template<class charT,class traits=char_traits<charT> > 
  class ostreambuf_iterator;

  template<class charT,class traits=char_traits<charT> > 
  class istreambuf_iterator;

  template<class charT,class traits=char_traits<charT> > 
  class basic_iostream;

  template<class charT,class traits=char_traits<charT>,
           class Allocator = allocator<charT> >
  class basic_stringstream;

  template<class charT,class traits=char_traits<charT> > 
  class basic_fstream;

  // specializations on tiny characters
  typedef basic_ios<char>              ios;
  typedef basic_streambuf<char>        streambuf;
  typedef basic_istream<char>          istream;
  typedef basic_ostream<char>          ostream;
  typedef basic_stringbuf<char>        stringbuf;
  typedef basic_istringstream<char>    istringstream;
  typedef basic_ostringstream<char>    ostringstream;
  typedef basic_filebuf<char>          filebuf;
  typedef basic_ifstream<char>         ifstream;
  typedef basic_ofstream<char>         ofstream;
  typedef basic_iostream<char>         iostream;
  typedef basic_stringstream<char>     stringstream;
  typedef basic_fstream<char>          fstream;

  // specializations on wide characters
  typedef basic_ios<wchar_t>           wios;
  typedef basic_streambuf<wchar_t>     wstreambuf;
  typedef basic_istream<wchar_t>       wistream;
  typedef basic_ostream<wchar_t>       wostream;
  typedef basic_stringbuf<wchar_t>     wstringbuf;
  typedef basic_istringstream<wchar_t> wistringstream;
  typedef basic_ostringstream<wchar_t> wostringstream;
  typedef basic_filebuf<wchar_t>       wfilebuf;
  typedef basic_ifstream<wchar_t>      wifstream;
  typedef basic_ofstream<wchar_t>      wofstream;
  typedef basic_iostream<wchar_t>      wiostream;
  typedef basic_stringstream<wchar_t>  wstringstream;
  typedef basic_fstream<wchar_t>       wfstream;

  // positional types used by char_traits
  typedef fpos<mbstate_t> streampos;
  typedef fpos<mbstate_t> wstreampos;

  typedef long streamoff;
  typedef long wstreamoff;
}

fpos, char_traits, basic_ios, basic_streambuf, basic_istream, basic_ostream, basic_iostream, basic_stringbuf, basic_istringstream, basic_ostringstream, basic_stringstream, basic_filebuf, basic_ifstream, basic_ofstream, basic_fstream, istreambuf_iterator, ostreambuf_iterator

ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.2