How to configure environment to build python-embedded c code with LLVM Clang

Question

I'm trying to compile a program written in c that has python embedded in it.

I ran python3.3-config -cflags to get the cflags I've used in this command.

% >> clang -v einformer.c -o einformer - I/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -I/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -Wno-unused-result -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/usr/local/include -I/usr/local/opt/sqlite/include
Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.2.0
Thread model: posix
"/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.8.0 -emit-obj -disable-free -disable-llvm-verifier -main-file-name einformer.c -pic-level 2 -mdisable-fp-elim -masm-verbose -munwind-tables -target-cpu core2 -target-linker-version 136 -v -g -resource-dir /usr/bin/../lib/clang/4.2 -D NDEBUG -I /usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -I /usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -I /usr/local/include -I /usr/local/opt/sqlite/include -fmodule-cache-path /var/folders/lz/5nhsdlnn3x9g8ry_mkgtgh500000gp/T/clang-module-cache -c-isystem /usr/include/python2.6 -c-isystem . -O3 -Wno-unused-result -Wall -Wstrict-prototypes -fdebug-compilation-dir /Users/ardentapprentice/dev/osx/test -ferror-limit 19 -fmessage-length 140 -fwrapv -stack-protector 1 -mstackrealign -fblocks -fobjc-runtime=macosx-10.8.0 -fobjc-dispatch-method=mixed -fobjc-default-synthesize-properties -fno-common -fdiagnostics-show-option -fcolor-diagnostics -o /var/folders/lz/5nhsdlnn3x9g8ry_mkgtgh500000gp/T/einformer-T6nymD.o -x c einformer.c
clang -cc1 version 4.2 based upon LLVM 3.2svn default target x86_64-apple-darwin12.2.0
ignoring duplicate directory "/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m"
ignoring duplicate directory "/usr/local/include"
  as it is a non-system directory that duplicates a system directory
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m
 /usr/local/opt/sqlite/include
 /usr/include/python2.6
 .
 /usr/local/include
 /usr/bin/../lib/clang/4.2/include
 /usr/include
 /System/Library/Frameworks (framework directory)
 /Library/Frameworks (framework directory)
End of search list.
einformer.c:92:25: warning: implicit declaration of function 'PyString_AsString' is invalid in C99 [-Wimplicit-function-declaration]
    path_array[i] = PyString_AsString(pypath);
                    ^
1 warning generated.
 "/usr/bin/ld" -demangle -dynamic -arch x86_64 -dynamic -macosx_version_min 10.8.0 -o einformer /var/folders/lz/5nhsdlnn3x9g8ry_mkgtgh500000gp/T/einformer-T6nymD.o -lSystem /usr/bin/../lib/clang/4.2/lib/darwin/libclang_rt.osx.a
Undefined symbols for architecture x86_64:
  "_PyList_GetItem", referenced from:
      _main in einformer-T6nymD.o
  "_PyList_Size", referenced from:
      _main in einformer-T6nymD.o
  "_PyRun_SimpleStringFlags", referenced from:
      _main in einformer-T6nymD.o
  "_PyString_AsString", referenced from:
      _main in einformer-T6nymD.o
  "_Py_Finalize", referenced from:
      _main in einformer-T6nymD.o
  "_Py_Initialize", referenced from:
      _main in einformer-T6nymD.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

It seems as though clang is having trouble locating headers maybe? <Python.h> is included in the source I'm not sure what I'm doing wrong :/

Ive spent about 3 hours looking through the python documentation http://docs.python.org/3.3/c-api/index.html and googling around, but I cant seem to find any information that helps me.

It seems to have found the headers fine but not the libraries. Maybe add --libs to your python3.3-config (assuming it's a similar system to pkg-config)? — tangrs
– tangrs, Commented Feb 26, 2013 at 9:35
running python3.3-config --libs gives me -ldl -framework CoreFoundation -lpython3.3m are these the locations of the libraries on my system? how do I tell clang where the libraries are? — joshua.thomas.bird
– joshua.thomas.bird, Commented Feb 26, 2013 at 9:57
Try to find the where these libraries are and try to export the env variable LDFLAGS — dmg
– dmg, Commented Feb 26, 2013 at 10:09
I'm using zsh; when the env variable is exported, it is added to my .zshrc as LDFLAGS=/usr/local/Frameworks/Python.framework/Versions/3.3/lib/ where the dylibs have been symlinked? or should this be the libraries under /Library/Frameworks/Python.framework/Versions/3.3/lib/ — joshua.thomas.bird
– joshua.thomas.bird, Commented Feb 26, 2013 at 10:59

bdash · Accepted Answer · 2013-02-27 07:10:34Z

1

python3.3-config --cflags only gives the arguments needed to find the headers. python3.3-config --ldflags will give you the linker flags. This means that you should be able to compile your program with a compiler invocation something like:

clang -v einformer.c -o einformer $(python3.3-config --cflags) $(python3.3-config --ldflags)

answered Feb 27, 2013 at 7:10

bdash

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