[Cython] Use of long type for intermediate integral variables

[Ian Henriksen]

On Thu, Jul 2, 2015 at 9:50 PM Robert Bradshaw <robertwb at math.washington.edu>
wrote:

> To clarify, any choice of int64_t + unsigned long will be wrong on one
> platform or the others, but getting the wrong sign seems preferable to
> getting the wrong number of bits.
>

That makes sens. Thanks for looking at it!
-Ian Henriksen


>
> On Thu, Jul 2, 2015 at 8:45 PM, Robert Bradshaw
> <robertwb at math.washington.edu> wrote:
> > I've fixed this particular case by making our integer ranking more
> > consistent: signedness is ignored for anything but chars and typedefs
> > are always preferred (as a last tiebreaker) over non-typedefs (rather
> > than arbitrarily picking the first or second argument).
> >
> https://github.com/cython/cython/commit/61ee8e544bd8802dfc313d832f5da97baf755c3d
> >
> > I've also upgraded the definition of int64_t to be long long to avoid
> > issues with int64_t + unsigned long. There's still an issue of int32_t
> > + unsigned int for any platforms where sizeof(int) == 16.
> >
> >  -Robert
> >
> > On Thu, Jul 2, 2015 at 1:11 PM, Ian Henriksen
> > <insertinterestingnamehere at gmail.com> wrote:
> >> On Thu, Jul 2, 2015 at 1:08 PM Robert McGibbon <rmcgibbo at gmail.com>
> wrote:
> >>>
> >>> Right, okay. I think I understand.
> >>>
> >>> -Robert
> >>>
> >>> On Thu, Jul 2, 2015 at 12:58 AM, Stefan Behnel <stefan_ml at behnel.de>
> >>> wrote:
> >>>>
> >>>> Robert McGibbon schrieb am 02.07.2015 um 09:49:
> >>>> >> "libc.stdint.int64_t" is hand-wavingly declared as "long"
> >>>> >
> >>>> > There are some deeper issues in the rest of your message, but as a
> >>>> > preliminary matter, isn't this a clear error for linux-32 and
> windows?
> >>>>
> >>>> No, it's not. That's just what Cython sees. The C compiler then sees
> the
> >>>> exact platform specific type. And as the vast amount of Cython code
> out
> >>>> there shows, it's usually not a problem in practice. Cython is
> designed
> >>>> to
> >>>> handle most of these "platform specific type" issues at C compile time
> >>>> rather than C code generation time. But as your example shows, it
> can't
> >>>> always hide the details entirely. And there can be bugs.
> >>>>
> >>>> Stefan
> >>>>
> >>>> _______________________________________________
> >>>> cython-devel mailing list
> >>>> cython-devel at python.org
> >>>> https://mail.python.org/mailman/listinfo/cython-devel
> >>>
> >>>
> >>> _______________________________________________
> >>> cython-devel mailing list
> >>> cython-devel at python.org
> >>> https://mail.python.org/mailman/listinfo/cython-devel
> >>
> >>
> >> This is an interesting discussion. Thanks.
> >> For the particular case of int64_t, wouldn't it still be wise to
> >> make it a typedef of long long rather than just long so as to
> consistently
> >> get the correct size on platforms where long
> >> is only 32 bits?
> >> Thanks!
> >> -Ian Henriksen
> >>
> >> _______________________________________________
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> >> cython-devel at python.org
> >> https://mail.python.org/mailman/listinfo/cython-devel
> >>
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