What is the difference between basic_istream and istream?

    2 answers 2

    basic_istream is a template:

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

    istream and wistream are aliases (*) of this template, for cases when charT is char and wchar_t respectively.

     using istream = basic_istream<char>; using wistream = basic_istream<wchar_t>;

    *) The term “specialization” or “instantiation” could be used here, but with reference to using and typedef , these terms cause much controversy (in particular, we do not know whether basic_istream<char> implemented as explicit specialization or not).

    • @ixSci corrected the answer. - Abyx

    There is no difference between them, because istream is nothing more than basic_istream<char> .

    • Well, I would still say that one is a special case of the second. - VladD
    • @VladD, as far as I remember, there is no separate specialization there, so it’s inappropriate to speak about a particular case, as it seems to me. This is a simple instantiation. - ixSci
    • Well yes. I istream is basic_stream<char> , that is, it is a specific template instantiation. And basic_istream is just the template itself. A special case is not in the sense of inheritance. - VladD