Re: VFS: C99 sparse format for struct vfsops

From: Paul Richards <paul_at_freebsd-services.com>
Date: Thu, 5 Jun 2003 17:17:23 +0100
On Thu, Jun 05, 2003 at 04:06:16PM +0100, Doug Rabson wrote:
> On Thu, 2003-06-05 at 15:51, Paul Richards wrote:
> > On Wed, Jun 04, 2003 at 02:43:20PM +0100, Doug Rabson wrote:
> > > On Wed, 2003-06-04 at 14:16, Paul Richards wrote:
> > > > On Wed, Jun 04, 2003 at 01:33:46PM +0100, Doug Rabson wrote:
> > > > 
> > > > > Interfaces actually can be added at runtime. Existing objects (i.e.
> > > > > objects instantiated before the new interface was added) will continue
> > > > > to work as before. If methods from the new interface are called on old
> > > > > objects, the default method will be called.
> > > > 
> > > > How can you add an interface at runtime?
> > > 
> > > By loading a kernel module. If I load e.g. the agp kernel module, I add
> > > the agp_if interface to the kernel.
> > 
> > Yes, I know that you can load a pre-compiled interface at runtime
> > and thereby add that interface, but you can only "create" interfaces
> > at build time because each method in the interface is uniquely
> > identified by a kobjop_desc struct, which is what I was referring to.
> 
> What has build time got to do with anything? At build time, you have no
> idea what interfaces are available either. Besides modules can be built
> at a different time from the rest of the kernel.

My point was simply that interfaces can't be "created" other than
at compile time because the kobjop_desc structures are used as
unique identifiers. I wasn't making this point in relation to the
discussion on knowing what methods are in the class, just from the
point that interfaces can't be created or modified at runtime.

-- 
Tis a wise thing to know what is wanted, wiser still to know when
it has been achieved and wisest of all to know when it is unachievable
for then striving is folly. [Magician]
Received on Thu Jun 05 2003 - 07:17:25 UTC

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