cython: Symbol Undefined...

I have read multiple examples for generating an so library using cython’s pure python interface, and then later calling a function in it. THE FUNCTION IS NOT GETTING DEFINED IN THE SO!

• The pure python code:

#cython: language_level=3

import cython

@cython.cfunc
@cython.returns(cython.int)
@cython.locals(a=cython.int)
def blah(a):
    return 42

• The cython command: cython3 test.py
• The gcc step: gcc -fpic `python3-config --cflags` -o test.o -c test.c
• generate an so from the compilation output: gcc -shared -o test.so test.o `python3-config --libs`
• List the entrypoints in the so:

nm -D test.so|less
# (I'm not seeing the function "blah" there!)

• Try accessing the so:

python3
from ctypes import CDLL
so=CDLL('./test.so')
dir(so)
['_FuncPtr', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattr__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_func_flags_', '_func_restype_', '_handle', '_name'] 
# NO "blah" function!

All the pure python examples take it as a given that it will show up.

cython version: 0.29.30 python version: 3.9.2 gcc version: 10.2.1 ctypes version: 1.1.0 OS: Debian 11