Date: Wed, 11 Feb 2009 22:51:02 +0100 From: Christoph Mallon <christoph.mallon@gmx.de> To: Aniruddha Bohra <abohra@gmail.com> Cc: hackers@freebsd.org, Andriy Gapon <avg@icyb.net.ua> Subject: Re: a little bit of c++ in kernel [module] Message-ID: <49934846.10905@gmx.de> In-Reply-To: <43a2dc1a0902110840t1e4c8856lb5b33cc153ea4acb@mail.gmail.com> References: <43a2dc1a0902101243w5ce35609x35dbe440c39d80a8@mail.gmail.com> <4992D1B0.8020708@icyb.net.ua> <43a2dc1a0902110840t1e4c8856lb5b33cc153ea4acb@mail.gmail.com>
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Aniruddha Bohra schrieb: > On Wed, Feb 11, 2009 at 8:25 AM, Andriy Gapon <avg@icyb.net.ua> wrote: >> on 10/02/2009 22:43 Aniruddha Bohra said the following: >>> You can see Click: http://read.cs.ucla.edu/click/ >>> It does not run on FreeBSD >4. >>> I have an old diff which builds on the work by Marko Zec and Bruce >>> Simpson, that allows me to load the click module. >>> http://www.cs.rutgers.edu/~bohra/click-1.5.0.diff >> 1. options -fpermissive -fno-exceptions -fno-rtti are passed to c++ compiler >> 2. there are new/delete implementations that use kernel malloc >> >> I think that #1 means that there are no exceptions, (non-trivial) >> dynamic_cast and typeid for kernel c++ code. > > Correct. That's a pity. Lack of exceptions negates some major benefits of C++. >> 1. do you use any global/static objects with constructors? did you have >> to write any code to call on those constructors when the module is loaded? > > Not sure about this one. But AFAIK, there are no global static objects > with constructors in Click code. > There is one router object that is always initialized and it is > updated by writing to the clickfs file system. > The other objects are created with new. > >> 2. did you have to write any other run-time support code or platform >> glue code (besides new/delete)? > > Apart from the new and delete, I think the other things were the > pseudofs code to initialize the file system, > the locks in include/click/sync.hh, the glue code in atomic.hh. > > >> 3. I assume virtual inheritance can be used in kernel code? do you use it? Virtual inheritence needs no support from the "outside", so it is available. > Yes. For example, all objects inherit from "Element" and that defines > virtual functions. (include/click/element.hh) Virtual inheritance is something completely different than virtual methods.
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