Initial trait definition for relocatable

[isidorostsa]

This is a draft pr to implement the basic traits for P1144 (relocatable).

I defined a meta function (is_relocatable) and pointer_relocate_category allongside the existing pointer_copy_category and pointer_move_category.

A type is relocatable if it is not tied to a specific location in memory. (An example object that is not relocatable is std::mutex)

The aim of this branch is to implement the trivially relocatable trait and the faster data transfer algorithms it allows us to use.

To move forward I ask if this is the right file to the is_relocatable definitions.

I believe the trivially_copyable_pointer part of this file focuses on if an iterator is suitable for a contiguous memcpy, and not in determining if the underlying object is trivially_copyable; it uses std::is_trivially_copyable for that. At the moment however there is no std::is_trivially_relocatable or std::is_relocatable, so these have to be implemented first.

At the moment I have placed hpx::is_relocatable in this file, should I place it somewhere else?

Thanks!

[StellarBot]

Can one of the admins verify this patch?

[gonidelis]

Maybe adding tests would help :)

[hkaiser]

LGTM, thanks! However, please fix the clang-format and cmake-format issues.

[gonidelis]

I like it. is_relocatable = is_move_constructible && is_destructible is a simple idea on which we can build upon.

[hkaiser]

@isidorostsa Wrt testing: I think having a couple of tests would be nice, most likely compile tests using static_assert that verify the traits really do what you expect. Please have a look at the exiting testing infrastructure for clues on how to do that.

[isidorostsa]

@isidorostsa Wrt testing: I think having a couple of tests would be nice, most likely compile tests using static_assert that verify the traits really do what you expect. Please have a look at the exiting testing infrastructure for clues on how to do that.

Thanks for the hints, I will add the tests later today

[hkaiser]

@isidorostsa Please don't think we're ignoring this. Let's wait for the release of HPX V1.9.0 (next week) before merging.

[isidorostsa]

@isidorostsa Please don't think we're ignoring this. Let's wait for the release of HPX V1.9.0 (next week) before merging.

@hkaiser That's great to hear!

I wanted to ask you, was I correct to add my name to the copyrights list section of all the files I changed?
Also is there a specific HPX macro for static assertions or is static_assert okay?

[hkaiser]

wanted to ask you, was I correct to add my name to the copyrights list section of all the files I changed?

The rule of thumb we usually apply is that one should add his/her name to the copyrights whenever the person touched on ~20% of the file.

Also is there a specific HPX macro for static assertions or is static_assert okay?

static_assert() is just fine.

[hkaiser]

@isidorostsa could you please rebase this onto master, now that the release is out?

[isidorostsa]

@isidorostsa could you please rebase this onto master, now that the release is out?

I think I did it, but could you confirm that as this is not something I've done before? Thanks!

[hkaiser]

@isidorostsa could you please rebase this onto master, now that the release is out?

I think I did it, but could you confirm that as this is not something I've done before? Thanks!

LGTM, thanks.

[hkaiser]

I think this is good to be merged. LGTM, thanks!

[hkaiser]

bors merge

[bors]

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• Bors

[hkaiser]

@isidorostsa Congratulations, your first PR to the HPX repository has just been merged! As a 'thank you' we offer a free STE||AR-Group t-shirt to all of our first-time contributors. If you are interested in receiving one, please get back to me directly so we can set up the delivery.

[hkaiser]

@isidorostsa after merging your PR, compilation is failing across the board, see for instance here: https://github.com/STEllAR-GROUP/hpx/actions/runs/4893500203/jobs/8736534493. Would you have the time to investigate?

[hkaiser]

@isidorostsa after merging your PR, compilation is failing across the board, see for instance here: https://github.com/STEllAR-GROUP/hpx/actions/runs/4893500203/jobs/8736534493. Would you have the time to investigate?

Please see #6233 for a possible fix.

[isidorostsa]

@isidorostsa after merging your PR, compilation is failing across the board, see for instance here: https://github.com/STEllAR-GROUP/hpx/actions/runs/4893500203/jobs/8736534493. Would you have the time to investigate?

Hello, yes, getting to it rn