configure section for libev looks for event.h

[NateCrawford]

Background information

What version of the PMIx Reference Library are you using?

4.2.8

Describe how PMIx was installed

tarball

Please describe the system on which you are running

• Operating system/version:
  Rocky 8.9
• Computer hardware:
  x86_64
• Network type:
  Infiniband

---

Details of the problem

When running configure, the libev tests fail when they can't find event.h. The header file provided by libev-devel is ev.h, and we don't have the corresponding libevent-devel package installed.

I'm guessing it's a typo, as manually editing the configure script to test for ev.h completes as expected.

Here? -->

openpmix/config/pmix_setup_libev.m4

Line 66 in 00d43d2

[event.h],

[NateCrawford]

In this case compilation is still blocked by a number of files still including event.h.

For now, dropping back to use libevent instead of libev.

[rhc54]

What version of libev are you using? Sounds like he made a change as there has been no previous problem with using it.

[NateCrawford]

The package installed from the EL8 OS "appstream" repo is libev-devel-4.24-6.el8.x86_64. It provides:
/usr/include/ev++.h
/usr/include/ev.h
/usr/lib64/libev.so
/usr/share/man/man3/ev.3.gz

4.24 was originally released in 2016, and can provide its own version of event.h as a compatibility wrapper. This would, however, conflict with libevent-devel's event.h, so I assume the packagers left that out. I'll look into it.

If you compile libev and install somewhere else, there's probably no issue.

Can pmix be modified to use ev.h directly when libev is used?

[NateCrawford]

And a little more searching gets this package in the repo: libev-libevent-devel-4.24-6.el8.x86_64, which contains the missing event.h wrapper. It obviously conflicts with the libevent-devel package, so there would still be a small benefit to having pmix not use event.h if libev is chosen.

Testing config and build with libev now.

[NateCrawford]

Config and build with the wrapper event.h work, but the self-tests hang and fail with a timeout. That, however, would be a different issue, and this one can probably be closed.

For now, going with libevent-2.1.8-5.el8

[rhc54]

I don't know the last time someone used libev - no real benefit to doing so over libevent. We only added that support because someone was using a package based on libev, and there are too many conflicts if you try to link against both event libraries. Haven't heard anything recently about it, to be honest.

I'll leave this open so we can look at it, but it will be a low priority so I cannot say when we might get to it.

[NateCrawford]

Sounds good to me. I did not know libev existed until recently, and don't need to use it. If libevent is used more widely, I'll go with that.

If you do start to look at it, and can't reproduce the tests hanging when using libev, let me know.

Thanks!