undefined reference to `PyCMethod_New'

[EnziinSystem]

My environment:

Ubuntu 20.04
Python 3.8.10

When I run compile a program use pybind11, it raise a error:

/usr/bin/ld: ../scripting/libscripting.a(python_scripting.cpp.o): in function `pybind11::cpp_function::initialize_generic(std::unique_ptr<pybind11::detail::function_record, pybind11::cpp_function::InitializingFunctionRecordDeleter>&&, char const*, std::type_info const* const*, unsigned long)':
/home/../ubuntu/kicad/thirdparty/pybind11/include/pybind11/pybind11.h:415: undefined reference to `PyCMethod_New'
collect2: error: ld returned 1 exit status
make[2]: *** [bitmap2component/CMakeFiles/bitmap2component.dir/build.make:191: bitmap2component/bitmap2component] Error 1
make[1]: *** [CMakeFiles/Makefile2:3754: bitmap2component/CMakeFiles/bitmap2component.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....

[jiwaszki]

Without minimal example it is hard to tell, but I think that linking is source of your problem.

Look at these two stacks:

• https://stackoverflow.com/a/61085569
• https://stackoverflow.com/questions/27672572/embedding-python-in-c-linking-fails-with-undefined-reference-to-py-initialize

[Keepmoving-ZXY]

The same problem in my project, and I am working on a simple cast to reproduct this error.

[G-Pereira]

What was the issue @Keepmoving-ZXY ? I need to fix it in mine as well

[Keepmoving-ZXY]

According to my memory, I solve this problem by changing another version of python.

[G-Pereira]

That and updating from Ubuntu 20.04 to 22.04, and updating pyside fixed it for me as well. Here was my changes (I did not test which was the culprit):

https://github.com/opulo-inc/lumenpnp/commit/7d21ffdd5ba38b47300d0af594ac255632f6c074

[NumbNutN]

Hi, I've solve the problem by update my Python interpreter version to 3.9.18. There's definitely no symbol definition for PyCMethod_New in libpython3.8.so. But I can find it in libpython3.9.so

$ readelf -s lib/libpython3.9.so | grep "PyCMethod"
   489: 0000000000121070   460 FUNC    GLOBAL DEFAULT   11 PyCMethod_New
  1921: 0000000000365ac0   408 OBJECT  GLOBAL DEFAULT   21 PyCMethod_Type
   443: 00000000000696d4   103 FUNC    LOCAL  DEFAULT   11 PyCMethod_New.cold
 36122: 0000000000121070   460 FUNC    GLOBAL DEFAULT   11 PyCMethod_New
 37245: 0000000000365ac0   408 OBJECT  GLOBAL DEFAULT   21 PyCMethod_Type

Notice PyCMethod_New is part of the stable ABI in Python Standard Library since version 3.9. Python Doc - PyCMethod_New