Hartmut Kaiser

> `ranges::fold_left_first` and `ranges::fold_right_first` return std::optional type (C++17) `ranges::fold_left_with_iter` and `ranges::fold_left_first_with_iter` return std::in_value_result (C++23) > > so should we enable fold algorithms only if HPX compiled with C++23 std? No,...

> We would have to deviate from the standard. We could alternately work on `hpx::in_value_result` that does seem better. Yes, that would have to be added as well. I thin...

> sure, do we have a hpx::optional? if so do you suggest returning it instead of std::optional? If not, do we plan on implementing it? Yes, please use `hpx::optional`, it...

@isidorostsa would you be able to have a look why the relocation test is failing (https://cdash.cscs.ch/viewTest.php?onlyfailed&buildid=116017)?

I'm putting this on ice for the time being. From what I see, p2079 is not implementable the way it's specified.

This PR causes tests to fail. I've moved it to the next milestone.

@AndreyKulikov2022 Sorry for the late response... I believe this has been fixed on HPX master. Could you please try again?

> I am installing hpx 1.9.1 via vcpkg. I've checked the problem with the latest version that vcpkg provides. Unfortunately the same error remains. You could build HPX using vcpkg...

@Pansysk75 Yep, that's caused by the direct execution patch. cancelable_action should call `get_outer_id` instead (here: https://github.com/STEllAR-GROUP/hpx/blob/bc993dd15b9252908e0b30b9ed5efd830cf99909/examples/cancelable_action/cancelable_action/server/cancelable_action.hpp#L61). Excellent catch!

> @Pansysk75 Yep, that's caused by the direct execution patch. cancelable_action should call `get_outer_id` instead (here: > > https://github.com/STEllAR-GROUP/hpx/blob/bc993dd15b9252908e0b30b9ed5efd830cf99909/examples/cancelable_action/cancelable_action/server/cancelable_action.hpp#L61 > > ). Excellent catch! I just realized that we don't...