Re: [LINUX-KERNEL] C++ in linux kernel

From: Joonwoo Park
Date: Fri Feb 08 2008 - 19:45:45 EST


2008/2/9, Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>:
>
> On Feb 9 2008 00:14, Joonwoo Park wrote:
> >2008/2/8, rohit h <hrohit85@xxxxxxxxx>:
> >> Hi,
> >> I am a kernel newbie.
> >> I tried to insmod a C++ module containing classes, inheritance.
> >> I am getting 'unresolved symbol' error when I use the 'new' keyword.
> >> What could the problem be?
> >>
> >> What kind of runtime support is needed ( arm linux kernel)? Is a
> >> patch available for it?
> >>
> >Please take a look at click modular router which is using c++ as a
> >linux kernel module.
> >http://www.read.cs.ucla.edu/click/
> >The lib/glue.cc provides custom operator new.
>
> Uh, let's not make the world worse :)
> Just call malloc from C++, and carefully select what C++ features
> you are going to use. The VMware source for example does it right.
>

Yep, also I think that if kmalloc is possible it would better than the
operator new.

Rohit,
Compiling the kernel module with g++ is not a simple work, you may
need big patch for kernel itself.
The c++ has more internal keywords than c.
e.g) new, delete, and ::
The new and delete should be re-spelled with another names.
The '::' is used in inline assembly however in c++ it means global namespace.

In conclusion, I don't recommand c++ for linux kernel without very
special goal like the click project :)

Joonwoo
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