Re: boost.spawn: review requested

From: Oliver Kowalke (oliver.kowalke_at_[hidden])
Date: 2021-11-30 21:40:49

Andrey Semashev via Boost <boost_at_[hidden]> schrieb am Di., 30. Nov.
2021, 21:00:

> 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

It's described in the C++ proposal ...
lifecycle, stack must be managed + ownership and state (for instance
resuming an already running fiber).