DragonFly kernel List (threaded) for 2009-01
Re: C++ in the kernel
On Sun, Jan 04, 2009 at 05:06:13PM +0100, Michael Neumann wrote:
> This question bugs me since a quite long time so I write it down...
> FreeBSD had a long thread about pros and cons of using C++
> in the kernel here .
> I'm undecided whether it would be good to use C++ in the DragonFly kernel.
> At first, most importantly, there is the question about the quality of
> the C++ compiler (bug-freeness) and the quality of the generated machine
> I can't answer this for sure, just did a small test compiling
> the same C code with both a C and a C++ compiler. Both produce the same
> machine code.. Using C++ classes without all the more advanced stuff
> (like exception, RTTI...) shouldn't make too much a difference in the
> produced code. So I don't think this will be much of a problem.
> Next thing to consider is the possible abuse of C++'s features
> (exceptions, RTTI etc.). I don't think this is a problem either,
> especially in a small project like DragonFly, as there is only a handful
> of developers. The solution to this problem is as simple as just don't
> use those features.
> Now to the advantages of C++ that IMO would make sense:
> * Think about the kobj and the driver architecture. All this comes
> for free when using C++. No .m files anymore. Everything in
> one language.
> * Think about macro-driven datastructures (e.g. rbtree).
> They are IMHO quite unreadable and very hackish.
> C++ templates on the other hand are a lot cleaner
> (they are sometimes ugly as well :).
> Of course templates doesn't help when using internal
> datastructures like sys/queue.h.
> Maybe I spent too much time using OO languages (like Ruby or C++).
> What I am missing most in C is the ability to subclass structures,
> methods and templates. All this IMHO can improve expressability
> and code quality.
I can't pretend to know what this implies for DfBSD, I think Linus has
addressed this before wrt Linux:
I don't know enough C++ to share his opinion, nor do I contribute to
any projects, but I think this might be some good background on the