[C++-sig] Boost python and import error

[Valentino Volonghi]

hi all, I'm trying to use boost to write python extensions in C++ under OSX.

I'm trying to use the most basic example of a greet function. The
extension module
is inside a reactor package and it's called _reactor.

Unfortunately after a compilation (that successfully finishes) I get
the following error:
>>> from reactor import _reactor
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "reactor/__init__.py", line 11, in <module>
    from reactor import _reactor
ImportError: dynamic module does not define init function (init_reactor)

I've searched for this on google and found many answers but none
worked. Actually
after looking at boost/python.hpp source I think that init_reactor
should be there
since it's inserted by BOOST_PYTHON_MODULE macro. Do I really have to use
boost.jam to compile this small example? (I ask because I tried hard
to use it under
osx last week and failed miserably, I simply can't use it and
documentation is lacking at best).

Thanks for information!

Here is the full source:
#include <boost/python.hpp>

using namespace boost::python;

char const* greet()
{
   return "hello, world";
}

BOOST_PYTHON_MODULE(_reactor)
{
    def("greet", greet);
}

and here's the setup.py:

#!/usr/bin/python
import sys, os
from os.path import join
from distutils.core import setup
from distutils.extension import Extension
from distutils import sysconfig

# break abstraction to set g++ as linker - is there better way?
sysconfig._init_posix()
compiler = "g++ -ftemplate-depth-50"
#compiler += " -fkeep-inline-functions" # for debugging

# workaround for bugs in Redhat 7.3 compiler
if os.popen("g++ --version").read().strip() == "2.96":
    compiler += " -fno-inline "

sysconfig._config_vars["CC"] = compiler
if sys.platform == 'darwin':
    sysconfig._config_vars["LDSHARED"] = "g++ -undefined dynamic_lookup"
else:
    sysconfig._config_vars["LDSHARED"] = "g++ -shared"

ext_modules = []
include_dirs = ["./include", "/usr/local/include", "/opt/local/include/"]
if os.environ.has_key("BOOST_INCLUDE"):
    include_dirs.append(os.environ["BOOST_INCLUDE"])

libraries = []
for libpath in (os.environ.get("LD_LIBRARY_PATH", "").split(":") +
["/usr/lib", "/lib", "/usr/local/lib", "/opt/local/lib/"]):
    paths = [os.path.join(libpath, libname) for libname in
("libboost_python.so", "libboost_python.dylib")]
    for path in paths:
        if os.path.exists(path):
            libraries.append("boost_python")
            break
if not "boost_python" in libraries:
    libraries.append("boost_python-gcc-mt")



ext_modules.append(Extension("reactor._reactor", [join("reactor",
"%s.cpp" % name) for name in
                                                  ("_reactor",)],
                             libraries=libraries,
                             library_dirs=["/usr/local/lib", "/opt/local/lib"],
                             include_dirs=include_dirs))

setup(
  name = "reactor",
  packages=["reactor"],
  ext_modules=ext_modules,
)


-- 
Valentino Volonghi aka Dialtone
Now running MacOS X 10.4
TechBlog: http://vvolonghi.blogspot.com
Home Page: http://www.twisted.it