Re: C++ / multiple instances / iostreams

[Laurence Finston]

> Hans Aberg wrote:
-------------------
> 
> I believe that the design criterion that BS expressed was that C++ should
> admit efficient implementations, but by no means as optimized as in C. Sed
> the book DEC++ ("Design and Evolution of C++").
> 
> >  One of the important
> >goals in the design of C++ was also not to lose the ability to program in a
> >low-level style efficiently.
> 
> Right: C++ is a multiparadigm language. But the high level cannot be as
> efficient as optimized low-level programming.
> 

I just read a relevant passage in _The C++ Programming Language_ the other
day, but unfortunately I don't have it here, so I can't quote it at you.  In
both that book and _The Design and Evolution_ Stroustrup is very firm that C++
should be as efficient as C when only the common subset of C and C++ is used. 
He argues, persuasively I think, for all of the features in C++ that are not
in C, and for the features provided by the standard library, that  the
cost/benefit ratio is always reasonable.   Of course, an implementation may be
particulary efficient or inefficient.

>From my point of view,  in the case of an inefficient implementation of, say,
a standard library template class, my solution would be use it anyway, and
hope that the implementors of `libstdc++' improve it, as I'm confident they
will do.  After all, my package isn't used for anything people's lives depend
on.

On the other hand, if I thought that C++ was significantly less efficient than
C, I would have used C.   "Optimized" to me means optimized for a particular
machine.   I'm not sure I'll ever get around to doing this, but I am curious
whether implementing matrix multiplication and inversion in assembler would
produce a performance benefit.

It was interesting to look at your code. 

Laurence