I'm trying to compile a file that makes use of Python's C API. I'm working in a conda enviroment, running on macOS Monterey. I'm compiling using GCC as following:
gcc -c -fPIC file.c -I "${CONDA_PREFIX}/include/python3.9/" -o file.o
gcc file.o -o a.out
The problem is not of inclusion of the <Python.h> header, that is done properly, it seems like once the Python library is included its function's symbols are undefined:
Undefined symbols for architecture x86_64:
"_PyCallable_Check", referenced from:
_main in file.o
"_PyImport_ImportModule", referenced from:
_main in file.o
"_PyObject_CallObject", referenced from:
_main in file.o
"_PyObject_GetAttrString", referenced from:
_main in file.o
...
I'm sure the problem isn't with the code since I'm running some demo code from Python's official website. The same error occours when trying to develop a python module using Python C API, compiling as shared library.
I also tried compiling the whole thing using distutils/setuptools, the error is kilometric, but the substance is the same as the above one.
The above exception was obtained using this demo code.
Output of ls ${CONDA_PREFIX}/lib ${CONDA_PREFIX}/lib/python3.9
/opt/anaconda3/envs/generic/lib:
Tk.icns libncurses.6.dylib
Tk.tiff libncurses.dylib
clang libncursesw.6.dylib
dtrace libncursesw.dylib
engines-3 libnode.102.dylib
icu libomp.dylib
itcl4.2.1 libpanel.6.dylib
libbz2.1.0.8.dylib libpanel.dylib
libbz2.a libpanelw.6.dylib
libbz2.dylib libpanelw.dylib
libc .1.0.dylib libpython3.9.a
libc .1.dylib libpython3.9.dylib
libc .a libpython3.9.nolto.a
libc .dylib libquadmath.0.dylib
libc experimental.a libquadmath.dylib
libcrypto.3.dylib libreadline.8.1.dylib
libcrypto.dylib libreadline.8.dylib
libffi.8.dylib libreadline.dylib
libffi.a librustc-stable_rt.asan.dylib
libffi.dylib librustc-stable_rt.lsan.dylib
libform.6.dylib librustc-stable_rt.tsan.dylib
libform.dylib librustc_driver-5d5e1e2505841b99.dylib
libformw.6.dylib libsqlite3.0.dylib
libformw.dylib libsqlite3.dylib
libgcc_s.1.dylib libssl.3.dylib
libgcc_s_ppc64.1.dylib libssl.dylib
libgcc_s_x86_64.1.dylib libstd-dd8a82589e0cba34.dylib
libgfortran.5.dylib libtcl8.6.dylib
libgfortran.dylib libtclstub8.6.a
libgomp.1.dylib libtest-a18e5b5e2a65c941.dylib
libgomp.dylib libtinfo.6.dylib
libhistory.8.1.dylib libtinfo.dylib
libhistory.8.dylib libtinfow.6.dylib
libhistory.dylib libtinfow.dylib
libicudata.69.1.dylib libtk8.6.dylib
libicudata.69.dylib libtkstub8.6.a
libicudata.dylib libuv.1.dylib
libicui18n.69.1.dylib libuv.a
libicui18n.69.dylib libuv.dylib
libicui18n.dylib libz.1.2.11.dylib
libicuio.69.1.dylib libz.1.dylib
libicuio.69.dylib libz.a
libicuio.dylib libz.dylib
libicutest.69.1.dylib node_modules
libicutest.69.dylib ossl-modules
libicutest.dylib pkgconfig
libicutu.69.1.dylib python3.9
libicutu.69.dylib rustlib
libicutu.dylib sqlite3.34.0
libicuuc.69.1.dylib tcl8
libicuuc.69.dylib tcl8.6
libicuuc.dylib tclConfig.sh
libiomp5.dylib tclooConfig.sh
liblzma.5.dylib tdbc1.1.2
liblzma.dylib tdbcmysql1.1.2
libmenu.6.dylib tdbcodbc1.1.2
libmenu.dylib tdbcpostgres1.1.2
libmenuw.6.dylib terminfo
libmenuw.dylib thread2.8.6
libncurses .a tk8.6
libncurses w.a tkConfig.sh
/opt/anaconda3/envs/generic/lib/python3.9:
LICENSE.txt mailbox.py
__future__.py mailcap.py
__phello__.foo.py mimetypes.py
__pycache__ modulefinder.py
_aix_support.py multiprocessing
_bootlocale.py netrc.py
_bootsubprocess.py nntplib.py
_collections_abc.py ntpath.py
_compat_pickle.py nturl2path.py
_compression.py numbers.py
_markupbase.py opcode.py
_osx_support.py operator.py
_py_abc.py optparse.py
_pydecimal.py os.py
_pyio.py pathlib.py
_sitebuiltins.py pdb.py
_strptime.py pickle.py
_sysconfigdata__darwin_darwin.py pickletools.py
_sysconfigdata__darwin_darwin.py.orig pipes.py
_sysconfigdata_x86_64_apple_darwin13_4_0.py pkgutil.py
_threading_local.py platform.py
_weakrefset.py plistlib.py
abc.py poplib.py
aifc.py posixpath.py
antigravity.py pprint.py
argparse.py profile.py
ast.py pstats.py
asynchat.py pty.py
asyncio py_compile.py
asyncore.py pyclbr.py
base64.py pydoc.py
bdb.py pydoc_data
binhex.py queue.py
bisect.py quopri.py
bz2.py random.py
cProfile.py re.py
calendar.py reprlib.py
cgi.py rlcompleter.py
cgitb.py runpy.py
chunk.py sched.py
cmd.py secrets.py
code.py selectors.py
codecs.py shelve.py
codeop.py shlex.py
collections shutil.py
colorsys.py signal.py
compileall.py site-packages
concurrent site.py
config-3.9-darwin smtpd.py
configparser.py smtplib.py
contextlib.py sndhdr.py
contextvars.py socket.py
copy.py socketserver.py
copyreg.py sqlite3
crypt.py sre_compile.py
csv.py sre_constants.py
ctypes sre_parse.py
curses ssl.py
dataclasses.py stat.py
datetime.py statistics.py
dbm string.py
decimal.py stringprep.py
difflib.py struct.py
dis.py subprocess.py
distutils sunau.py
doctest.py symbol.py
email symtable.py
encodings sysconfig.py
ensurepip tabnanny.py
enum.py tarfile.py
filecmp.py telnetlib.py
fileinput.py tempfile.py
fnmatch.py test
formatter.py textwrap.py
fractions.py this.py
ftplib.py threading.py
functools.py timeit.py
genericpath.py tkinter
getopt.py token.py
getpass.py tokenize.py
gettext.py trace.py
glob.py traceback.py
graphlib.py tracemalloc.py
gzip.py tty.py
hashlib.py turtle.py
heapq.py turtledemo
hmac.py types.py
html typing.py
http unittest
idlelib urllib
imaplib.py uu.py
imghdr.py uuid.py
imp.py venv
importlib warnings.py
inspect.py wave.py
io.py weakref.py
ipaddress.py webbrowser.py
json wsgiref
keyword.py xdrlib.py
lib-dynload xml
lib2to3 xmlrpc
linecache.py zipapp.py
locale.py zipfile.py
logging zipimport.py
lzma.py zoneinfo
My CONDA_PREFIX is /opt/anaconda3/envs/generic
CodePudding user response：
This command: gcc file.o -o a.out does not link to a python library.
You need to add (append) -lpython3 and possibly -L${CONDA_PREFIX}/lib/python3.9 to it.
CodePudding user response：
Try adding this to your linking command:
-L${CONDA_PREFIX}/lib -lpython3.9
This should tell the linker to use the libpython3.9.a file I see in your directory listing.
By the way, I imagine Conda comes with some configuration tool that outputs these same options, so you wouldn't have to hardcode the Python version number.