Undefined symbol when importing Python Sybase module on OSX 10.6

Question

I'm trying to get the python-sybase module working on OSX 10.6, but I've run into a bit of a snag.

When I do

import Sybase

I get

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "Sybase.py", line 15, in <module>
    from sybasect import *
ImportError: dlopen(/Library/Python/2.6/site-packages/python_sybase-0.40pre2-py2.6-macosx-10.6-universal.egg/sybasect.so, 2): Symbol not found: _blk_alloc
  Referenced from: /Library/Python/2.6/site-packages/python_sybase-0.40pre2-py2.6-macosx-10.6-universal.egg/sybasect.so
  Expected in: flat namespace
 in /Library/Python/2.6/site-packages/python_sybase-0.40pre2-py2.6-macosx-10.6-universal.egg/sybasect.so

I took a look at sybasect.so, and sure enough, _blk_alloc is undefined. The function is located in Sybase's sybblk.dylib, which is installed, and its containing directory is in LD_LIBRARY_PATH.

When I compiled python-sybase using python setup.py build, the gcc command appears to find all of the right libs correctly, but for some reason those libs don't appear to be linked after installing sybasect.so to the Python module dir.

The gcc command is

gcc-4.2 -Wl,-F. -bundle -undefined dynamic_lookup -arch i386 -arch ppc -arch x86_64 build/temp.macosx-10.6-universal-2.6/blk.o build/temp.macosx-10.6-universal-2.6/databuf.o build/temp.macosx-10.6-universal-2.6/cmd.o build/temp.macosx-10.6-universal-2.6/conn.o build/temp.macosx-10.6-universal-2.6/ctx.o build/temp.macosx-10.6-universal-2.6/datafmt.o build/temp.macosx-10.6-universal-2.6/iodesc.o build/temp.macosx-10.6-universal-2.6/locale.o build/temp.macosx-10.6-universal-2.6/msgs.o build/temp.macosx-10.6-universal-2.6/numeric.o build/temp.macosx-10.6-universal-2.6/money.o build/temp.macosx-10.6-universal-2.6/datetime.o build/temp.macosx-10.6-universal-2.6/date.o build/temp.macosx-10.6-universal-2.6/sybasect.o -L/Applications/Sybase/System/OCS-15_0/lib -lsybblk -lsybct -lsybcs -lsybtcl -lsybcomn -lsybintl -lsybunic -o build/lib.macosx-10.6-universal-2.6/sybasect.so

The -L/Applications/Sybase/System/OCS-15_0/lib location is correct, and that folder contains all of the right .dylib's.

When I run otool the output is:

$ otool -L build/lib.macosx-10.6-universal-2.6/sybasect.so
build/lib.macosx-10.6-universal-2.6/sybasect.so:
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.11)

I was expecting to see the Sybase libs in there.

I'm a little new to linking on Mac. How do I ensure that sybasect.so references the Sybase libs?

Answer 1

Fixed it.

The problem was that the various Sybase libraries I was linking to were 32-bit only, but I was running Python in 64 bit mode. The fix was just running python in 32-bit mode.

I used the command defaults write com.apple.versioner.python Prefer-32-Bit -bool yes since I don't have any particular need for 64 bit mode.