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

[Sebastian Haase]

On 10/9/07, Ray Schumacher <subscriber100 at rjs.org> wrote:
> 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:
>
> <snip>
> 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?

Maybe that's why it crashed ;-) !?  But for simple use it seems fine.

>
> >(( 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
> http://aspn.activestate.com/ASPN/Mail/Message/ctypes-users/3192422
> of creating a numpy array from a raw address (not a c_array).
>
I assume this is a different issue, but haven't looked into it yet.

-Sebastian