Date: Thu, 21 Apr 2005 14:21:58 -0400 From: Aziz KEZZOU <opensource.enthousiat@gmail.com> To: Chuck Robey <chuckr@chuckr.org> Cc: hackers@freebsd.org Subject: Re: KLD module with C++ iostreams ? Message-ID: <37e1316605042111215c201be9@mail.gmail.com> In-Reply-To: <42670F63.4000901@chuckr.org> References: <37e1316605042019072b5d7a0e@mail.gmail.com> <5bbfe7d4050420191316a629b7@mail.gmail.com> <42670F63.4000901@chuckr.org>
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> David Leimbach wrote:
> > Interesting question. People usually have to implement the C++
> > runtime to be usable from within the kernel. Things like exceptions
> > and "stdout" may not be defined in kernel space :)
> >
> > I'm not terribly familiar with how it works on FreeBSD but I know it
> > took a special effort to get C++ support into linux.
> >
> > Dave
> >
> > On 4/20/05, Aziz KEZZOU <opensource.enthousiat@gmail.com> wrote:
> >
> >>Hi hackers,
> >>I am wondering if I can use c++ iostreams inside the kernel ?
> >>After all the code : cout << "Hello world!" << endl;
> >>ends accessing the stdout just like : printf("Hello world!\n"); right ?
>=20
> No, that's not true, all the iostreams stuff is totally independent.
> The iostreams stuff is coming from some of the ugliest code in C++.
> But, that's not the question, or at very least, it shouldn't BE the
> question. There is ZERO need to bring in features from C++, all it will
> do is to directly confuse the code base by greatly adding to the
> complexity of the code, without giving anything like equivalent features.
>=20
> Some very, very elegant work has been code, OO-ing the kernel code,
> adding OO features, all without violating the C language code base.
> Adding in C++ features over stdio stuff is so senseless, it's nearly
> obscene.
>=20
> If the gain at the end of the road was large enough, I wouldn't be
> against it so stridently, but I see *so* little gain.
>=20
> BTW, you know where the ugliest code in computer science today is: half
> is in the actual implementation of the cstdio/template code, the other
> half is the iostreams stuff. The fact that they energize some very
> elegant code is causing many folks never to see the fact of the horrible
> code lumps that exist out in the backyard.
>=20
> >>
> >>So if I could compile my KLD module with static linkage to libstdc++,
> >>that should be ok, right ?
> >>
> >>Any one did or knows how to do this ?
> >>
Thank you guys for responding to my post.
Certainly, it is not a good idea to use _all_ C++ stuff inside the
kernel ; in the linux community a similar suggestion resulted in a big
discussion of pros & cons. I was asking because I have a big portion
of C++ code that I am planning to move inside the kernel.
But, having compared the effort/time required to port C++ iostreams
into the kernel and the effort/time required to get rid of iostreams ,
I think I will abandon this challenge for now ;-)
Just to let you know "virtual methods" and "templates", among others,
are supported inside the kernel...
Greetings,
-aziz
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