Re: [boost] mistaken uses of <iostream>

From: John Maddock (john_at_[hidden])
Date: 2006-11-20 07:48:17

Howard Hinnant wrote:
> It has recently come to my attention that I could be overly sensitive
> to this issue and making a fuss about nothing.  So I'm writing here
> for a reality check.  Do boost programmers consider the use of
> <iostream> as a short cut to get to non-terminal-streams I/O a
> reasonable technique?  Or do boost programmers feel that use of
> <iostream> should be reserved only when using one or more of cin,
> cout, cerr, clog, wcin, wcout, wcerr, wclog?
>
> I did a brief survey of boost 1.33.1 and found many "relaxed" uses of
> <iostream> under the boost/ directory (i.e. non test-case code).  So
> in practice it does appear that using <iostream> as a shortcut is
> considered acceptable practice.  However I wanted to highlight the
> point just in case people do view this as a bug that has simply snuck
> in under the radar to date.

Well it snuck under *my* radar I admit.

I think the problem here is that it's tricky to ensure that you have all the 
necessary headers included: different implementations may or may not flag up 
an error depending which headers you've included, so including <iostream> is 
a sort of "belt-and-braces" approach.

But in principle you are correct.

As an aside, I've always wanted a sort of "conceptual" std lib 
implementation, that included in each header nothing except what absolutely 
has to be there.  Just the declarations would do, so we could do 
compile-time tests against it to verify inclusion of the right headers: the 
only tricky bit is getting the compile time constants correct so that it can 
still compile meta code.  Any volunteers? :->

John.