[ET Trac] [Einstein Toolkit] #1717: hwloc: lnuma & lltdl *really* required?

[Einstein Toolkit]

#1717: hwloc: lnuma & lltdl *really* required?
------------------------------------+---------------------------------------
  Reporter:  zachetie@…             |       Owner:                     
      Type:  defect                 |      Status:  new                
  Priority:  minor                  |   Milestone:                     
 Component:  EinsteinToolkit thorn  |     Version:  development version
Resolution:                         |    Keywords:                     
------------------------------------+---------------------------------------

Comment (by knarf):

 Replying to [comment:15 eschnett]:
 > Frank -- what do you suggest concretely?

 I agree with Ian, as in that this should be reported either to Ubuntu, or
 possibly to upstream hwloc, depending on where we think the error lies.
 Until this is fixed, I think it would be sensible to use the workaround,
 which we could document well enough so that in the future this can be
 easily understood, and removed again.

 Having said that: If I read the following correctly, this could be a
 rather interesting problem:
 http://www.open-mpi.org/community/lists/hwloc-devel/2013/05/3743.php

 The problem seems to be that when used as dynamical library, hwloc does
 _not_ depend on libltdl as "usual dynamic library", but can load it later
 by itself, if found (dynamically, but ldd does not see that). If built
 statically of course, ltdl would need to be linked in for it to be usable.
 So, if I read this correctly, the hwloc-dev package has the option of
 depending on the other two libraries at build-time, but does not have to
 (it builds without these libraries, but it can use these libraries in a
 dynamic setup). Does anybody here agree to my interpretation?

 That leaves the user with an installed hwloc that uses both numa and ltdl
 if present (because it was compiled with support for them), and the
 library correctly reports the link-dependencies both for dynamic and
 static linking. However, the -dev package does not have a dependency on
 the other two library packages because they are optional, at least for the
 dynamic libraries that are typically used on the system. So, the problem
 is: should the hwloc-dev package depend on the numa/ldtl libraries? It
 should for static linking, and should not for dynamic linking. Since the
 hwloc package only provides the dynamic version, and since by far the
 majority of users would link dynamically, their decision to not add the
 dependency is correct in my eyes.

 Now the question would be: what do we do in this situation? We could test
 for these libraries to be present when we build hwloc and link statically,
 and give a better error message.

-- 
Ticket URL: <https://trac.einsteintoolkit.org/ticket/1717#comment:16>
Einstein Toolkit <http://einsteintoolkit.org>
The Einstein Toolkit