ctypes listing dll functions

[Tim Roberts]

marc.wyburn at googlemail.com wrote:
>
>hi all and before I start I apologise if I have this completely muddled
>up but here goes.
>
>I'm trying to call functions from a dll file in a python script but I
>can't work out what functions are available. I'm using ctypes.  I've
>tried using dir(ctypes_object) but the resultant output looks like a
>list of standard functions and not the ones I'm looking for.

As far as I know, there is no way with ctypes to enumerate the functions
exported by a DLL.  If you have Visual C++, you can use link.exe to do
this:
    link /dump /exports xxxxx.dll

>Also how can I tell if the dll was written in C or C++ as I understand
>C++ dlls can't be used.

Well, DLLs that use C++ features cannot be used.  If the exported names are
"decorated", then they can't be used.

>I have a header file that starts;
>
>#ifndef __DIRAC__
>#define __DIRAC__
>
>    // Prototypes
>
>    const char *DiracVersion(void);
>    void *DiracCreate(long lambda, long quality, long numChannels,
>float sampleRate, long (*readFromChannelsCallback)(float **data, long
>numFrames, void *userData));
>    void *DiracCreate(long lambda, long quality, long numChannels,
>float sampleRate, long (*readFromChannelsCallback)(float *data, long
>numFrames, void *userData));

That's called "function overloading": two functions with the same name but
slightly different parameters.  That is only available with C++, so I'm
afraid you are out of luck.  You may be able to use SWIG to generate an
interface for this; I've had good luck with SWIG.
-- 
- Tim Roberts, timr at probo.com
  Providenza & Boekelheide, Inc.