[std-discussion] Coroutine stack location and addresses

Discussion:

Itaj Sherman

2018-11-19 00:17:00 UTC

Is it supposed to be legal for coroutine A, to take a reference to a local
variable (on it's own stack) and pass it to another coroutine or main
thread to access the object while coroutine A is not running?
Whether it passes the pointer through the coroutine return API or by
writing it in a static structure.

itaj

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Victor Dyachenko

2018-11-19 09:23:42 UTC

Permalink

I suppose it's legal for stackful coroutines (Boost.Context,
Boost.Coroutine2) but illegal for stackless ones (co_await/Gog-routines)

Itaj Sherman

2018-11-19 11:32:14 UTC

Permalink

Post by Victor Dyachenko
I suppose it's legal for stackful coroutines (Boost.Context,
Boost.Coroutine2) but illegal for stackless ones (co_await/Gog-routines)

Maybe the intention is that if the compiler sees a reference to a local
object that is possibly passed outside the coroutine, it has to allocate
the object itself at a stable location, and only keep a pointer on its own
execution stack.
So it could be legal, and technically then, it doesn't have to be
mentioned, but I guess it should be for clarity.