Re: Transparent bridges (a. k. a. HUB-to-PCI bridges)?

From: Charles Swiger <cswiger_at_mac.com>
Date: Wed, 24 Nov 2004 15:29:25 -0500
On Nov 24, 2004, at 1:41 PM, John-Mark Gurney wrote:
>> True OOP involves encapsulation, polymorphism, and inheritence, and
>> requires language support which is not really available in pure C.  
>> That
>> being said, careful programming in C lets you create several
>> closely-related structs for different types of "objects" which can 
>> all be
>> utilized by a common set of functions.
>
> You should read up on KOBJ's which is how device_t's are implemented
> in FreeBSD...  kobj's are a loop more OOP that you think...

OK.  I've taken a look at sys/kobj.h and sys/kern/subr_kobj.c, is there 
something else I should read?

My take on it, for what it is worth, is that KOBJs implement the class 
versus instance paradigm, have a dynamic runtime & method dispatch 
rather similar to the implementation of Objective-C or virtual C++ 
methods.  Yes, this is a lot more object-oriented than what I said 
about being disciplined using C struct's.  :-)

Things that one still doesn't have is encapsulation in the sense of 
data hiding; what Java calls protected or private ivar's.  Object 
memory management for instances via reference counting or GC would also 
be nice, although I even saw a hint of that in kobj_delete(), as well 
as a bit of the alloc/init & delete/free seperation.

-- 
-Chuck
Received on Wed Nov 24 2004 - 19:29:27 UTC

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