[iostream.forward.overview] (original) (raw)

31 Input/output library [input.output]

31.3 Forward declarations [iostream.forward]

31.3.2 Overview [iostream.forward.overview]

The class template specializationbasic_ios<charT, traits>serves as a virtual base class for the class templatesbasic_istream,basic_ostream, and class templates derived from them.

basic_iostreamis a class template derived from bothbasic_istream<charT, traits>andbasic_ostream<charT, traits>.

The class template specializationbasic_streambuf<charT, traits>serves as a base class for class templatesbasic_stringbuf,basic_filebuf, andbasic_syncbuf.

The class template specializationbasic_istream<charT, traits>serves as a base class for class templatesbasic_istringstreamandbasic_ifstream.

The class template specializationbasic_ostream<charT, traits>serves as a base class for class templatesbasic_ostringstream,basic_ofstream, andbasic_osyncstream.

The class template specializationbasic_iostream<charT, traits>serves as a base class for class templatesbasic_stringstreamandbasic_fstream.

[Note 1:

For each of the class templates above, the program is ill-formed iftraits​::​char_typeis not the same type ascharT ([char.traits]).

— _end note_]

Other typedef-names define instances of class templates specialized forcharorwchar_ttypes.

Specializations of the class templatefposare used for specifying file position information.

[Example 1:

The typesstreamposandwstreamposare used for positioning streams specialized oncharandwchar_trespectively.

— _end example_]

[Note 2:

This synopsis suggests a circularity betweenstreamposandchar_traits<char>.

An implementation can avoid this circularity by substituting equivalent types.

— _end note_]