Cython unable to find shared object file

Question

I am trying to link to my own C library from Cython, following the directions I\'ve found on the web, including this answer:

Using Cython To Link Python To A Shared

Answer 1

I'm self-answering, in case anyone else runs into the same problem. Looks like the answers are here:

Set LD_LIBRARY_PATH before importing in python

Changing LD_LIBRARY_PATH at runtime for ctypes

According to these answers (and my experience), the linker reads LD_LIBRARY_PATH when python is launched, so changing it from within python doesn't have any useful effect, at least not the effect I was hoping for. The only solution is to either wrap python in a shell script that sets LD_LIBRARY_PATH, or else drop the shared object somewhere on the linker search path.

Kind of a pain, but it is what it is.

Answer 2

I have fixed it by change setup.py.

1. I have a C++ dynamic shared library called "libtmsmdreader.so". and a header file named "TmsMdReader.hpp"
2. I wrapper C++ shared library to cython library called "tmsmdreader-pythonxxxxxx.so"

from setuptools import setup 
from distutils.extension import Extension
from Cython.Build import cythonize

setup(
    name="tmsmdreader",
    ext_modules=cythonize([
        Extension(
            name="tmsmdreader",
            language="c++",
            sources=["TmsMdReaderApi.pyx"],
            libraries=["tmsmdreader"],
            library_dirs=["."],
            include_dirs=["."],
            extra_compile_args=["-std=c++14"],
            compiler_directives={'language_level': 3},
            runtime_library_dirs=["."])
            ]))

library_dirs=["."] and runtime_library_dirs=["."] can fixed LD_LIBRARY_PATH if libtmsmdreader.so in python scripy directory