[Coin-discuss] Symbol not found loading libCoinMP from Python ctypes

[Stuart Mitchell]

Hi Josh,
why do you want to use CoinMP with pulp anyway?

The recommended/ default solver is command line cbc.

CoinMP uses and old version of cbc and has several unresolved bugs.

Stu

On Mon, Oct 13, 2014 at 11:13 AM, Joshua Arnott <josh at snorfalorpagus.net>
wrote:

> Miles,
>
> Thanks. Using the '--enable-dependency-linking' argument seems to work.
>
> However, I am now having trouble with a segfault with the following code
> which exists with the call to CoinReadFile. I have the same segfault trying
> to use PuLP. The same code runs fine on Linux.
>
> #!/usr/bin/env python3
>
> import ctypes
> lib = ctypes.CDLL('libCoinMP.dylib', ctypes.RTLD_GLOBAL)
> lib.CoinInitSolver('')
> lib.CoinGetVersionStr.restype = ctypes.c_char_p
> print(lib.CoinGetVersionStr())
> lib.CoinCreateProblem.restype = ctypes.c_int
> hprob = lib.CoinCreateProblem('test')
> cstr = ctypes.c_char_p(bytes('pack1.mps', 'utf-8'))
> print(lib.CoinReadFile(hprob, 3, cstr))
> lib.CoinFreeSolver()
>
> Josh
>
> On 11 October 2014 19:02, Miles Lubin <miles.lubin at gmail.com> wrote:
>
>> Hi Joshua,
>>
>> Try adding the '--enable-dependency-linking' argument to configure.
>>
>> Miles
>>
>> On Fri, Oct 10, 2014 at 5:57 PM, Joshua Arnott <josh at snorfalorpagus.net>
>> wrote:
>>
>>> Hello,
>>>
>>> I’m trying to use the CoinMP library from Python 3 via ctypes. When I
>>> try to load the shared library I get the following error:
>>>
>>> Python 3.4.1 (default, May 19 2014, 13:10:29)
>>> [GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
>>> Type "help", "copyright", "credits" or "license" for more information.
>>> >>> import ctypes
>>> >>> lib = ctypes.CDLL('libCoinMP.dylib')
>>> Traceback (most recent call last):
>>>   File "<stdin>", line 1, in <module>
>>>   File
>>> "/usr/local/Cellar/python3/3.4.1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/ctypes/__init__.py",
>>> line 351, in __init__
>>>     self._handle = _dlopen(self._name, mode)
>>> OSError: dlopen(libCoinMP.dylib, 6): Symbol not found: _CbcOrClpRead_mode
>>>   Referenced from: /usr/local/lib/libCoinMP.dylib
>>>   Expected in: flat namespace
>>>  in /usr/local/lib/libCoinMP.dylib
>>>
>>> However, when I “make test” everything runs correctly.
>>>
>>> Output from “nm” reports the symbol is undefined:
>>>
>>> U _CbcOrClpRead_mode
>>>
>>> I am getting similar errors for the other libraries, e.g.:
>>>
>>> Python 3.4.1 (default, May 19 2014, 13:10:29)
>>> [GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
>>> Type "help", "copyright", "credits" or "license" for more information.
>>> >>> import ctypes
>>> >>> ctypes.CDLL('libClp.dylib')
>>> Traceback (most recent call last):
>>>   File "<stdin>", line 1, in <module>
>>>   File
>>> "/usr/local/Cellar/python3/3.4.1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/ctypes/__init__.py",
>>> line 351, in __init__
>>>     self._handle = _dlopen(self._name, mode)
>>> OSError: dlopen(libClp.dylib, 6): Symbol not found:
>>> __ZN18CoinMessageHandler13checkSeverityEv
>>>   Referenced from: /usr/local/lib/libClp.dylib
>>>   Expected in: flat namespace
>>>  in /usr/local/lib/libClp.dylib
>>>
>>> Running Mac OS X 10.9.5, with current CoinMP from SVN.
>>>
>>> Kind regards,
>>>
>>> Josh
>>>
>>> _______________________________________________
>>> Coin-discuss mailing list
>>> Coin-discuss at list.coin-or.org
>>> http://list.coin-or.org/mailman/listinfo/coin-discuss
>>>
>>>
>>
>
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>


-- 
Stuart Mitchell
PhD Engineering Science
Extraordinary Freelance Programmer and Optimisation Guru
www.stuartmitchell.com
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