strange issue with C extension using Py_BuildValue

[Mark Hammond]

On 11/02/2010 9:19 AM, bobicanprogram wrote:
> I'm am having "strange" problems with the code snip below.
>
> When this code is built on a 64bit Linux,  it would appear to work
> flawlessly.    When the source is rebuilt on a 32bit Linux it begins
> to crack in strange ways.   The issue seems to be associated with the
> sender field in the Py_BuildValue call.    The fact that sender is a
> pointer should mean that its value is an unsigned integer.    However,
> on the 32 bit build the failure is that the msgPtr->data value is
> "messed up".   If the format associated with the sender (a pointer)
> from "L" to "i" things work on the 32 bit side but break on the 64 bit
> side.

I expect that in a 32bit build of linux, a "long long" (the 'L' format) 
is still 64 bits.  You probably want something like:

Py_BuildValue("iNz#", ret, PyLong_FromVoidPtr(sender), &msgPtr->data, ret);

and PyLong_AsVoidPtr() for the other direction.

HTH,

Mark