Creating a PYD file

Stefan Behnel stefan_ml at
Mon Aug 23 13:02:01 CEST 2010

Rony, 19.08.2010 21:41:
> The question actually is, is a PYD file created from C faster then a
> PYD file from Pyrex ?

Most likely, yes.

However, when comparing to Cython instead of Pyrex, the answer really 
depends on your code. Cython cannot be faster than the equivalent C code, 
simply because it generates C code. However, if the Python call overhead 
matters (e.g. in thin wrappers around simple C functions), Cython easily 
wins because it uses various tweaks that you simply wouldn't write in your 
own C code. If the overhead can be ignored, hand tuned C code wins often 
but not always, with the obvious drawback of being much harder to write and 
much longer in lines of code.

Generally speaking, if you can avoid it, don't write the extension in C. 
You'll have your Cython code hand optimised long before your C code is even 
close to running. And in the long run, the maintenance cost will always be 
the dominating factor anyway.


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