Dependency shared library not loaded during importing submodule

[kerim371]

Hi,

I have a module and define a submodule

PYBIND11_MODULE(_h5geo, m) {
  py::module_::import("h5gtpy._h5gt");

#ifdef H5GEO_USE_GDAL
  py::module_ m_gdal = py::module_::import("osgeo._gdal");
  py::module_ m_ogr = py::module_::import("osgeo._ogr");
  py::module_ m_osr = py::module_::import("osgeo._osr");

  // create submodule for Spatial Reference Settings
  py::module m_sr = m.def_submodule("sr");
#endif

// DEFINE METHODS FOR MODULE AND SUBMODULE HERE

}

In cmake:

pybind11_add_module(_h5geo ${src_files_h5geopy} ${include_files_h5geopy})
target_include_directories(_h5geo PRIVATE ${CMAKE_SOURCE_DIR}/include)
target_link_directories(_h5geo PRIVATE pybind11)

target_link_libraries(_h5geo PRIVATE h5geo)
target_link_libraries(_h5geo PRIVATE magic_enum::magic_enum)
target_link_libraries(_h5geo PRIVATE mio::mio)
target_link_libraries(_h5geo PRIVATE units::units)

if(H5GEO_USE_THREADS)
  target_link_libraries(_h5geo PRIVATE TBB::tbb)
  target_link_libraries(_h5geo PRIVATE OpenMP::OpenMP_CXX)
endif()

if(H5GEO_USE_GDAL)
  target_link_libraries(_h5geo PRIVATE GDAL::GDAL)
  target_link_libraries(_h5geo PRIVATE ${GDAL_LIBS})  # must be linked or undef ref to GEOS
  target_include_directories(_h5geo PRIVATE ${GDAL_TOP_LEVEL_INCLUDE_DIR})
endif()

I compile the library on CentOS 7 and deploy on Ubuntu 20.04.
In python I do:

from h5geopy import _h5geo

On CentOS 7 everything works fine.
But on Ubunutu I get error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/jjj/Documents/tmp/lib/Python/lib/python3.9/site-packages/h5geopy/__init__.py", line 15, in <module>
    from h5geopy import _h5geo as h5geo
ImportError: /home/jjj/Documents/tmp/lib/Python/lib/python3.9/site-packages/h5geopy/_h5geo.cpython-39-x86_64-linux-gnu.so: undefined symbol: _ZN5h5geo2sr15setAngularUnitsERKSs

I understand that it can't load sr.setAngularUnits function because it probably doesn' load the libh5geo.so library.
But if I preliminary manually load that library:

from ctypes import *
lib = cdll.LoadLibrary('libh5geo.so')

then I'm able to load h5geopy._h5geo library on Ubuntu as well.

Why Ubuntu doesn't load the dependency library libh5geo.so during import h5geopy._h5geo? And how to solve that (except adding cdll.LoadLibrary to the init.py)?

And yes libh5geo.so is in LD_LIBRARY_PATH

Pybind11 version: v2.9.0