Building a python module and linking it against a MacOSX framework

Posted by madflo on Stack Overflow See other posts from Stack Overflow or by madflo
Published on 2010-04-06T12:01:41Z Indexed on 2010/04/06 12:03 UTC
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I'm trying to build a Python extension on MacOSX 10.6 and to link it against several frameworks (i386 only). I made a setup.py file, using distutils and the Extension object.

I order to link against my frameworks, my LDFLAGS env var should look like :

LDFLAGS = -lc -arch i386 -framework fwk1 -framework fwk2

As I did not find any 'framework' keyword in the Extension module documentation, I used the extra_link_args keyword instead.

Extension('test',
define_macros = [('MAJOR_VERSION', '1'), ,('MINOR_VERSION', '0')],
include_dirs = ['/usr/local/include', 'include/', 'include/vitale'],
extra_link_args = ['-arch i386',
                   '-framework fwk1',
                   '-framework fwk2'],
sources = "testmodule.cpp",
language = 'c++' )

Everything is compiling and linking fine. If I remove the -framework line from the extra_link_args, my linker fails, as expected. Here is the last two lines produced by a python setup.py build :

/usr/bin/g++-4.2 -arch x86_64 -arch i386 -isysroot /
-L/opt/local/lib -arch x86_64 -arch i386 -bundle
-undefined dynamic_lookup build/temp.macosx-10.6-intel-2.6/testmodule.o
-o build/lib.macosx-10.6-intel-2.6/test.so
-arch i386 -framework sgdosx -framework srtosx
-framework ssvosx -framework stsosx

Unfortunately, the .so that I just produced is unable to find several symbols provided by this framework. I tried to check the linked framework with otool. None of them is appearing.

$ otool -L test.so
test.so:
    /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.0.1)

There is the output of otool run on a test binary, made with g++ and ldd using the LDFLAGS described at the top of my post. On this example, the -framework did work.

$ otool -L vitaosx 
vitaosx:
    /Library/Frameworks/sgdosx.framework/Versions/A/sgdosx (compatibility version 1.0.0, current version 1.0.0)
    /Library/Frameworks/ssvosx.framework/Versions/A/ssvosx (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.0.1)

May this issue be linked to the "-undefined dynamic_lookup" flag on the linking step ? I'm a little bit confused by the few lines of documentation that I'm finding on Google.

Cheers,

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