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Message-ID: <866d8a95-d7ff-475d-b8c5-bcffed0dfa1d@zytor.com>
Date: Thu, 11 Jan 2024 18:25:01 -0800
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Subject: Re: [PATCH 00/45] C++: Convert the kernel to C++
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To: David Howells <dhowells@redhat.com>
Cc: pinskia@gmail.com, Alexey Dobriyan <adobriyan@gmail.com>,
        linux-kernel@vger.kernel.org
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 <152261521484.30503.16131389653845029164.stgit@warthog.procyon.org.uk>
 <1681813.1704843645@warthog.procyon.org.uk>
From: "H. Peter Anvin" <hpa@zytor.com>
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On 1/9/24 15:40, David Howells wrote:
> 
>> Both C and C++ has had a lot of development since 1999, and C++ has in fact,
>> in my personal opinion, finally "grown up" to be a better C for the kind of
>> embedded programming that an OS kernel epitomizes.
> 
> And gcc got rewritten in C++ some time back, so they have a vested interest.
> 

Indeed.

>>>    (8) 'virtual'.  Don't want virtual base classes, though virtual function
>>>        tables might make operations tables more efficient.
>>
>> Operations tables *are* virtual classes. virtual base classes make sense in a
>> lot of cases, and we de facto use them already.
> 
> You end up adding storage for a 'this' pointer for each virtual base class, I
> think - and then you may have extra fun if you inherit from two classes that
> both inherit the same virtual base class.  Abstract base classes that are just
> ops tables are probably fine, though.

My apologies, I meant *abstract* base classes, not *virtual*. To be 
honest, I don't think I have ever used virtual base classes in any other 
application than games (relating to physical objects), and barely even then.

	-hpa