我如何在SWIG中包装一个C库，而SWIG通常在C编译期间被链接？

Question

Given a C-library, which has to be linked during compilation if I want to use its functions. I want to access these functions in Python using SWIG. I can only find examples and introductions where C-Code (example.c) is wrapped using SWIG, no method how to wrap a dynamic library (example.so).

Answer 1

All you need to do to make the .so (or .a) library case work is to link the library appropriately when you do the compile step of the example build process. You will still have to compile the example_wrap.c that gets generated, this is where you can link against things.

So modified from the SWIG docs that would be:

$ swig -python example.i
$ gcc -O2 -fPIC -c example.c
$ gcc -O2 -fPIC -c example_wrap.c -I/usr/local/include/python2.5
$ gcc -shared example_wrap.o -o _example.so -lmylib.so

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In reality you can also skip this at the compile time linker step and use dlopen at runtime instead by injecting some extra code into the Python part of your module that calls dlopen before the shared object from SWIG gets loaded.