[Numpy-discussion] numpy/Windows shared arrays between processes?

Ray Schumacher subscriber100@rjs....
Tue Oct 9 10:07:36 CDT 2007

At 05:22 AM 10/9/2007, David Cournapeau wrote:
>Could not this be because you compiled the posh sources with a
>compiler/runtime which is different than the other extensions and python
>interpreter ?

It definitely was - since my 2.4 wanted the free 7.1 compiler, I (and 
anyone else who didn't download it in time) are now seemingly SOL 
since it is no longer available. I saw much discussion of this as 
well, but even 2.5 is now "fixed" on 7.1 and reports of compiling 
distutil modules with the new MS SDK and having them work at all with 
2.4 were very mixed. I also tried GCC and had a litany of other 
errors with the posh.

>Sebastian Haase added:
>I was in fact experimenting with this. The solution seemed to lie in
>"simple" memmap as it is implemented in Windows:

I had just found and started to write some tests with that MS 
function. If I can truly write to the array in one process and 
instantly read it in the other I'll be happy. Did you find that locks 
or semaphores were needed?

>(( I have to mention, that I could crash a process while testing this ... ))

That was one of my first results! I also found that using ctypes to 
create arrays from the other process's address and laying a numpy 
array on top was prone to that in experimentation. But I had the same 
issue as Mark Heslep
of creating a numpy array from a raw address (not a c_array).

Ray Schumacher

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