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POWrapping a C library in Python: C, Cython or ctypes?
 

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  1. POWrapping a C library in Python: C, Cython or ctypes?
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    <p>I want to call a C library from a Python application. I don't want to wrap the whole API, only the functions and datatypes that are relevant to my case. As I see it, I have three choices:</p> <ol> <li>Create an actual extension module in C. Probably overkill, and I'd also like to avoid the overhead of learning extension writing.</li> <li>Use <a href="http://www.cython.org/" rel="noreferrer">Cython</a> to expose the relevant parts from the C library to Python.</li> <li>Do the whole thing in Python, using <a href="http://docs.python.org/library/ctypes.html" rel="noreferrer"><code>ctypes</code></a> to communicate with the external library.</li> </ol> <p>I'm not sure whether 2) or 3) is the better choice. The advantage of 3) is that <code>ctypes</code> is part of the standard library, and the resulting code would be pure Python &ndash; although I'm not sure how big that advantage actually is.</p> <p>Are there more advantages / disadvantages with either choice? Which approach do you recommend?</p> <hr> <p><strong>Edit:</strong> Thanks for all your answers, they provide a good resource for anyone looking to do something similar. The decision, of course, is still to be made for the single case&mdash;there's no one "This is the right thing" sort of answer. For my own case, I'll probably go with ctypes, but I'm also looking forward to trying out Cython in some other project.</p> <p>With there being no single true answer, accepting one is somewhat arbitrary; I chose FogleBird's answer as it provides some good insight into ctypes and it currently also is the highest-voted answer. However, I suggest to read all the answers to get a good overview.</p> <p>Thanks again.</p>
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    1. COTo some extent, the specific application involved (what the library does) may affect the choice of approach. We've used ctypes quite successfully to talk to vendor-supplied DLLs for various pieces of hardare (e.g. oscilloscopes) but I wouldn't necessarily pick ctypes first for talking to a numeric processing library, because of the extra overhead versus Cython or SWIG.
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      1. POWrapping a C library in Python: C, Cython or ctypes?
      1. USPeter Hansen
    2. CONow you have what were you looking for. Four different answers.(somebody also found SWIG). That mean that now you have 4 choices instead of 3.
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      1. USLuka Rahne
    3. CO@ralu That's what I thougt, too :-) But seriously, I didn't expect (or want) a pro/con table or one single answer saying "Here's what you need to do". Any question about decision making is best answered with "fans" of each possible choice giving their reasons. The community voting then does its part, as does my own work (looking at the arguments, applying them to my case, read provided sources, etc). Long story short: There are some good answers here.
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