a little bit of c++ in kernel [module]

[Aniruddha Bohra]

On Wed, Feb 11, 2009 at 8:25 AM, Andriy Gapon <avg at 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.

> 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?

Yes. For example, all objects inherit from "Element" and that defines
virtual functions. (include/click/element.hh)

Hope this helps.

Aniruddha