Re: boost.spawn: review requested

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2021-11-30 20:00:08

On 11/30/21 22:28, Peter Dimov via Boost wrote:
> Andrzej Krzemienski wrote:
>> Please correct me if I am wrong, but my understanding is that Boost.ASIO
>> works under C++03, and so does Boost.Coroutine. Whereas Boost.Coroutine2
>> requires C++11. If Boost.ASIO were to switch from BoostCoroutine to
>> Boost.Coroutine2, it would break its C++03 guarantee. (Some teams in my
>> work still have to use C++03.)
> 
> It's a bit more complex than that. Boost.Coroutine depends on Boost.Context,
> which is C++11. However, in order to not break C++03, Coroutine doesn't use
> the public API of Context, but the private "fcontext" parts that are kept C++03
> compatible only because of that. This incidentally means that if you compile
> Context with the `ucontext` backend instead of the `fcontext` one,
> Coroutine breaks.
> 
> So it's basically a mess and needs to be cleaned up. Since asio::spawn is a
> separate part of Asio, moving just it to C++11 wouldn't be as disruptive a
> change as requiring C++11 for all of Asio.

I wonder how much of Boost.Context actually requires C++11. From my
admittedly naive perspective, it should mostly be a bunch of assembler
bits and/or interface glue for system APIs like ucontext, none of which
inherently requires C++11.