Re: [boost] Boost.Threads, N2178, N2184, et al

From: Yuval Ronen (ronen_yuval_at_[hidden])
Date: 2007-03-24 18:44:18

Emil Dotchevski wrote:
> Here is how I understand your question: does it make sense to formalize a
> lower level API behind <thread>.

You understand correctly. This is the question I ask, and the answer I 
give is "no".

> If we lived in a world where pthreads did not exist, I wouldn't care much
> one way or another; but we don't.

The fact that pthreads exist is completely irrelevant. We setup a C++ 
standard, and it should be as good as it gets. The POSIX model is good, 
so we take it. The POSIX syntax is not so good (for C++, obviously) so 
we don't take it.

> So I think you're asking the wrong question.

I disagree. I think the question I'm asking is spot on, really. ;-)

> I think it's more appropriate
> to ask ourselves:
> 
> 1) Given that pthreads is already a very solid formal standard, and given
> that there is a lot of legacy code already written for it, does it make
> sense to also formally standardize it as the abstraction layer of the C++
> <thread> support?

Sorry, but I think not.

> 2) Does adopting pthreads as the standard lower level abstraction of the C++
> <thread> layer make it in any way harder to implement the C++ <thread>
> layer, compared to an implementation that does not formalize a lower level
> interface?
> 
> 3) Does a formal pthread layer introduce any overhead in the higher level
> C++ <thread> layer?

I haven't checked it in depth, but if you say no, then I'll take your 
word for it.

> In particular we need to examine the answer to 2) and 3) wrt the Windows
> <thread> implementation, since on Posix the answer is clear.

Disagreement again. Question 1 is not to be overlooked at all. The C++ 
moto is "don't pay for what you don't need". I'll add to that "don't 
standardize what you don't need". Less is more, and stuff like that.