The template class describes the storage and member functions common to both input streams (of template class basic_istream) and output streams (of template class basic_ostream) that depend on the template parameters. (The class ios_base describes what is common and not dependent on template parameters. An object of class basic_ios<class Elem, class Traits> helps control a stream with elements of type Elem, whose character traits are determined by the class Traits.
For a list of all members of this type, see.
A variable of type char_traits.
An object of class basic_ios<class Elem, class Traits> stores: