防止cin，cout，cerr被实例化

Question

As stated in this answer, when including iostream library the binary size gets much larger because the std::cin , std::cout , std::cerr (and maybe more) objects are created thus occupying a lot of memory.

I often compile code for embedded platforms which have strict constraints on memory. After including the iostream library the binary gets so big that it won't fit into the internal flash memory. That in turn affects the libraries which can be included, because a lot of them include <iostream> . One of example can be Protobuf library which I can't use across multiple projects as it includes iostream .

For those targets, which are run on an embedded platform, I don't need the objects to be created because I won't never use it. The question is: can I somehow prevent from creation of those objects? Is there maybe some other workaround which allows to include libraries which use iostream and to not increase the binary size so much?

Answer 1

You cannot in standard ways, because <iostream> is required to define these variables. If you do not want the variables then you have to include directly the headers (like <ios> , <streambuf> , <istream> , <ostream> and/or <iosfwd> ). I assume you want to include <iostream> for classes defined in those headers. If some third party library that you use includes things that you do not want then you have to consult with authors of such library, there are no generic answers.