Calling a shared library using C types

[Nathan Harmston]

On 25/03/2008, Gabriel Genellina <gagsl-py2 at yahoo.com.ar> wrote:
>
> En Mon, 24 Mar 2008 19:56:08 -0300, Nathan Harmston
> <iwanttobeabadger at googlemail.com> escribió:
>
>
> > import ctypes
> > t = ctypes.CDLL('./Simulation.so')
> > this works fine, I have a simple function I ve put in for testing which
> > just
> > returns the integer 4. However when I try to access this function it
> > doesnt
> > work
> > t.test()
> >  File "<stdin>", line 1, in <module>
> >   File
> >
> "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/ctypes/__init__.py",
> > line 325, in __getattr__
> >     func = self.__getitem__(name)
> >   File
> >
> "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/ctypes/__init__.py",
> > line 330, in __getitem__
> >     func = self._FuncPtr((name_or_ordinal, self))
> > AttributeError: dlsym(0x81e6b0, test): symbol not found
>
>
> Looks like the symbol isn't public - probably if you try loading the
> library with a C program it won't find it either. How is the function
> declared in the source?
> Try listing all public symbols with: nm -D Simulation.so

Thanks for the quick reply:
Running nm lists test as
00001760 T _test

in the source its declared as:

int test(){
    return 4;
}

Sorry, this is the first time I'm making my own shared library and using
ctypes, so being a little slow.

Thanks again

Nathan





> Im hoping python-list is ok for questions regarding ctypes :S
>
>
> It's not off topic, although there is a specific list for ctypes-related
> questions. But hijacking a thread to post a completely different question
> is not good netiquette.
>
> --
> Gabriel Genellina
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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