Deprecate all _x procedures

[martinruefenacht]

Problem

The _x procedures are replaced by the _c procedures which were introduced through the Embiggenment. Deprecating the _x procedures allows for removal in the next major version.

Proposal

Deprecate all _x procedures in the Standard.

Changes to the Text

• MPI_Type_get_extent_x
• MPI_Type_get_true_extent_x
• MPI_Get_elements_x
• MPI_Type_size_x
• MPI_Status_set_elements_x

---

• Added text about deprecation of _x procedures in the Deprecated Interfaces chapter (16).
• Moving all _x procedure definitions to the Deprecated Interfaces chapter.
• Replacing references to _x procedures with _c procedures since they are equivalent.
• Add procedures to Table 2.1
• Add Changelog entry

Impact on Implementations

None, with deprecation compliant implementations still need to implement the procedures.

Impact on Users

Deprecation has no immediate effect, anyone who uses _x procedures is strongly encouraged to swap to the corresponding _c procedure with the identical signature.

References

Previous PR was: https://github.com/mpi-forum/mpi-standard/pull/623
Fixed by: https://github.com/mpi-forum/mpi-standard/pull/829

[Wee-Free-Scot]

@martinruefenacht is this going to be on the agenda for a reading at the Dec 22 meeting? There's one unresolved review comment (replacements exist for Fortran), but otherwise its ready. It would be a shame for this to miss the MPI-4.1 release.

[wesbland]

This wasn't read at the December 2022 meeting. The last opportunity for MPI 4.1 is to have it ready at the March 2022 meeting (and it needs to "pass" the reading).

@martinruefenacht Are you (or is someone else) planning to push this forward or should we move it out of the plan for MPI 4.1?

[wesbland]

This passed a no-no vote on 2023-02-08.

Yes	No	Abstain
26	0	5

[mpiforumbot]

This passed a no-no vote.

Yes	No	Abstain
31	0	0

[mpiforumbot]

This passed a 1st vote.

Yes	No	Abstain
30	0	1

[wesbland]

This passed a 2nd vote.

Yes	No	Abstain
28	0	4