problem using ctypes with MMX intrinsics

Robert Kern robert.kern at gmail.com
Wed Oct 15 20:55:45 CEST 2008


dcharno wrote:
> Is it possible to use ctypes with a shared library which uses MMX/SSE 
> intrinsics?  I can load the library and access functions inside it, but 
> I getting a seg fault when I hit one of the intrinsics.  I'm wondering 
> if there might be some sort of stack alignment problem.
> 
> I am using gcc version 4.2.3 and Python 2.5.2 on Ubuntu 8.04.
> 
> Any suggestions would be helpful.

Well, stack alignment would be a problem with how the shared library gets 
compiled, nothing to do with ctypes (I think). However, if you are passing in 
arrays from ctypes, *they* may also be misaligned. Try to check the addresses of 
the ctypes values you are passing in. I'm not entirely sure how to do that, though.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco




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