Re: [boost] Request for 1.73 patch release

On Sat, 2 May 2020 at 23:09, Richard Hodges wrote:

Thank you all for your help and attention.

I have been spending the day investigating the root cause of compilation problems and extensively testing our fix.

In summary, I am inclined to de-escalate for now as I have discovered that neither

* clang-10 -std=c++20, nor * gcc-10 -std=c++20

will compile any asio program which involves a call to asio::co_spawn, which is fundamental requirement in a coroutine-enabled asio program.

What seems to be happening is that when concepts are enabled (which they are in the above compilers) asio is checking the result_of the supplied coroutine.

In clang-9 with -fcoroutines-ts, concepts are not enabled, so the check is not made.

I thinik I have been told previously by Lewis that it's not possible to take the result_of a coroutine. It's entirely possible that I have misunderstood as coroutine implementation is not yet my domain of expertise.

In summary, one of either (Asio && MSVC) || (clang && gcc) are in the wrong.

I am not qualified to say which at this stage.

I suspect there's a workaround in clang & gcc which will involve using macro definitions to convince asio that concepts are not available when compiled in c++20.

Confirmed: adding -DBOOST_ASIO_DISABLE_CONCEPTS to the command line options of clang-10 allows compilation.

It's late for me now but I'll check this train of thought in the morning.

R

On Sat, 2 May 2020 at 22:11, Robert Ramey via Boost wrote:

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On 5/2/20 10:44 AM, Vinnie Falco via Boost wrote:

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On Sat, May 2, 2020 at 9:34 AM Glen Fernandes wrote:

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A new release is costly

Understood. The problem is that the Boost 1.73 release as it is currently shipped, has a Beast that does not work with C++20 coroutines. Thus one or more other individuals besides me and Richard should decide if this is important enough to justify the cost of a new release. I can go either way on it. The fixes are stable and well tested.

We'll have another release in 2-4 months. I very much doubt that there are many users who are currently using Beast with C++20. And I don't see a huge hardship if those users need to wait a couple of months. I just don't see that a patch is worth all the extra work, including distribution, publicity, and confusion it might cause. Onward !!! don't waste time looking back.

better to spend a little more time to tweak the testing/release process so that such a thing can't recurre.

Robert Ramey

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Thanks

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-- Richard Hodges hodges.r@gmail.com office: +442032898513 home: +376841522 mobile: +376380212

-- Richard Hodges hodges.r@gmail.com office: +442032898513 home: +376841522 mobile: +376380212