Re: C++ in kernel (was Re: exception in a device driver)

Chip Salzenberg (chip@perlsupport.com)
Sat, 16 Jan 1999 02:24:17 -0500

According to Alexander Viro:
> On Sat, 16 Jan 1999, Chip Salzenberg wrote:
> > template <semaphore_t *SEM>
> > class hold {
> > public:
> > hold() { down(SEM); }
> > ~hold() { up(SEM); }
> > };
> >
> > void random_function()
> > {
> > hold<&one_semaphore> hold1;
> > hold<&other_semaphore> hold2;
> > // ...
> > }
>
> And if you'll call something that will throw an exception here it
> will compile to?

That's target-environment-dependent. The ELF object format provides
enough structure to assist in automatic cleanups; other environments
require cleanups to be done in ways more like hand-written C.

BTW, there are many places where you
> * release the lock on different pathes.
> * don't want to hold it too long.
> * release it from another function, called by you.
> * have to release a spinlock before the blocking operation.
> * have scopes incompatible with syntax ones,

A bit of code rearrangement can be required, yes. TANSTAAFL.

-- 
Chip Salzenberg      - a.k.a. -      <chip@perlsupport.com>
      "When do you work?"   "Whenever I'm not busy."


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