Vincent Vande Vyvre <vincent.vande.vy...@telenet.be> writes: > I am working on a python3 binding of a C++ lib. This lib is installed > in my system but the latest version of this lib introduce several > incompatibilities. So I need to update my python binding. > > I'm working into a virtual environment (py370_venv) python-3.7.0 is > installed into ./localpythons/lib/python3.7 > > So, the paths are: > # python-3.7.0 > ~/./localpythons/lib/python3.7/ > # my binding python -> libexiv2 > ~/./localpythons/lib/python3.7/site-packages/pyexiv2/*.py > ~/./localpythons/lib/python3.7/site-packages/pyexiv2/libexiv2python.cpython-37m-x86_64-linux-gnu.so > > # and the latest version of libexiv2 > ~/CPython/py370_venv/lib/libexiv2.so.0.27.0 > > All theses path are in the sys.path > > Now I test my binding: >>>> import pyexiv2 > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File > "/home/vincent/CPython/py370_venv/lib/python3.7/site-packages/py3exiv2-0.1.0-py3.7-linux-x86_64.egg/pyexiv2/__init__.py", > line 60, in <module> > import libexiv2python > ImportError: > /home/vincent/CPython/py370_venv/lib/python3.7/site-packages/py3exiv2-0.1.0-py3.7-linux-x86_64.egg/libexiv2python.cpython-37m-x86_64-linux-gnu.so: > undefined symbol: _ZN5Exiv27DataBufC1ERKNS_10DataBufRefE >>>> > > Checking the libexiv2.so the symbol exists > ~/CPython/py370_venv/lib$ objdump -T libexiv2.so.0.27.0 > .... > 000000000012c8d0 g DF .text 000000000000000f Base > _ZN5Exiv27DataBufC1ERKNS_10DataBufRefE > .... > > But it is not present into my old libexiv2 system, so I presume python use > /usr/lib/x86_64-linux-gnu/libexiv2.so.14.0.0 (The old 0.25) instead of > ~/CPython/py370_venv/lib/libexiv2.so.0.27.0 (The latest 0.27) > > How can I solve that ?
To load external C/C++ shared objects, the dynamic lickage loader (ldd) is used. "ldd" does not look at Pthon's "sys.path". Unless configured differently, it looks at standard places (such as "/usr/lib/x86_64-linux-gnu"). You have several options to tell "ldd" where to look for shared objects: * use the envvar "LD_LIBRARY_PATH" This is a "path variable" similar to the shell's "PATH", telling the dynamic loader in which directories (before the standard ones) to look for shared objects * use special linker options (when you link your Python extension shared object) to tell where dependent shared object can be found. -- https://mail.python.org/mailman/listinfo/python-list
