python - Changing LD_LIBRARY_PATH at runtime for ctypes

Question

How do you update this environment variable at runtime so that ctypes can load a library wherever? I've tried the following and neither seem to work.

from ctypes import *
os.environ['LD_LIBRARY_PATH'] = "/home/starlon/Projects/pyCFA635/lib"  
os.putenv('LD_LIBRARY_PATH', "/home/starlon/Projects/pyCFA635/lib")  
lib = CDLL("libevaluator.so")

question from:https://stackoverflow.com/questions/856116/changing-ld-library-path-at-runtime-for-ctypes

Answer 1

By the time a program such as Python is running, the dynamic loader (ld.so.1 or something similar) has already read LD_LIBRARY_PATH and won't notice any changes thereafter. So, unless the Python software itself evaluates LD_LIBRARY_PATH and uses it to build the possible path name of the library for dlopen() or an equivalent function to use, setting the variable in the script will have no effect.

Given that you say it doesn't work, it seems plausible to suppose that Python does not build and try all the possible library names; it probably relies on LD_LIBRARY_PATH alone.