cmake build produces incorrect "Extra libraries" in libhdf5.settings

[wkliao]

HDF5 version: 1.14.6

Using cmake to build HDF5 produces the following line in libhdf5.settings:

Extra libraries: m;dl

While using autoconf, the line looks normal:

Extra libraries: -lz -ldl -lm 

Here is the cmake command I used.

export CC=$HOME/MPICH/4.3.0/bin/mpicc
cmake ../hdf5-1.14.6 -D"HDF5_ENABLE_PARALLEL=ON"

[byrnHDF]

libhdf5.settings: is just text info not a build command option. The compression libraries are noted elswhere

[wkliao]

For an application user, how do I obtain the information of "Extra Libraries" of a given installed HDF5, other than its ibhdf5.settings?

[byrnHDF]

CMake produces config/target files in the CMake subfolder - Using CMake findpackage will provide complete targets and dependecies that are usable. Also, note that the compression libraries are static linked and do not expose any public APIs.

[wkliao]

I guess my question is more from an HDF5 user's point of view,, not a builder.
Given an already installed HDF5 library on a system, I need to know the
extra libraries used by HDF5, so I can add them to my application link command.

E3SM-IO extracts such information
from libhdf5.settings but failed to build due to the invalid results of Extra libraries.

[byrnHDF]

Yes, it was a coincidence that it could be used that way - however it should have used a different file built by autotools.
However for CMake there are better ways of getting that info. And you could still scrape information out of files if need be.
See the generated hdf5-targets.cmake file and the hdf5-config.cmake files. Also CMake generates pkg-config files that might work for you even better if you're not using CMake for your application.

[byrnHDF]

In the installation folder:

• cmake/hdf5-config.cmake file has a section showing what build options were used.
• cmake/hdf5-targets.cmake file has the properties for each target (search for the add_library() commands)
• lib/pkgconfig/hdf5.pc file has the "-l" lists

If you use cmake for your application then the find_package command will take care of dependecies and you can use the "options" listed in the cmake/hdf5-config.cmake file for checking capabilities.

Closing this, but feel free to reopen or create a new issue for more help.

[epourmal]

For an application user, how do I obtain the information of "Extra Libraries" of a given installed HDF5, other than its ibhdf5.settings?

Try "string" command on libhdf5.a or libhdf5.so file and save the output in the text file. Then search for "SUMMARY" Information that you see in the libhdf5.settings is encoded into the binary.

[wkliao]

Thanks for the suggestions. I am using the pkg-config solution now.

Can you clarify whether or not the strange strings shown in Extra libraries:
in file libhdf5.settings will be fixed in the next release?

[byrnHDF]

No, that is visual info and all the values in that file are pulled from the build commands.

[wkliao]

I think it should be fixed, as that info can be helpful, even if not directly used to build an application.

FYI. I did not add any additional library when building 1.14.6 on my local linux machine,
so nothing should show up on that line.

On Aurora at ALCF, it is:

Extra libraries: m;dl;/opt/aurora/24.180.3/spack/unified/0.8.0/install/linux-sles15-x86_64/oneapi-2024.07.30.002/mpich-4.3.0rc3-fzmrfta/lib/[libmpi.so](http://libmpi.so/)