[Python-Dev] ssize_t question: longs in header files

"Martin v. Löwis" martin at v.loewis.de
Mon May 29 23:43:54 CEST 2006

Thomas Wouters wrote:
>     Neal Norwitz wrote:
>     > minus comments, etc  yields several questions about whether some
>     > values should use Py_ssize_t rather than C longs.  In particular:
>     > * ints:  Include/intobject.h:    long ob_ival;
>     As Tim says, this is way out of scope for 2.5. Guido said it is ok
>     to change this to 64-bit ints in 2.6, but I expect some embedded
>     system developers will start screaming when they hear that: 64-bit
>     arithmetic is expensive on a 32-bit machine. 
> Well, those systems shouldn't have a 64-bit Py_ssize_t anyway, should they?

No - but Guido said he wanted Python int to have a 64-bit representation
everywhere, not a Py_ssize_t representation.

I agree using Py_ssize_t would be a "smaller" change, and one that
likely has less performance impact. It would still be a large change,
and should be only done if we know for sure we don't want it to be
a 64-bit type always the next day.


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