Re: [PATCH 3/3] Introduce $(compare ...) for numerical comparison

[Jouke Witteveen]

On Sun, Nov 28, 2021 at 3:20 PM Paul Smith <psmith@gnu.org> wrote:
>
> On Sun, 2021-11-28 at 14:57 +0100, Jouke Witteveen wrote:
> > > Since the two arguments are equal, it doesn't matter which of LHS
> > > or RHS we return.
> >
> > They could differ for instance when one of them contains a '+'-sign.
> > My reason for using LHS is that we already have a string for it.
>
> I don't think that it's necessary return the exact string.  If the user
> wanted a string match they can do that other ways.  Returning the
> "absolute value" (stripping leading +/-, leading 0's, etc.) seems more
> useful to me.

I fully agree, but was not aware of the robustness of INTSTR_LENGTH.
It felt a bit fragile when I spotted its definition in makeint.h.

> > > However, now that I think about it I need to change the code more: we
> > > need to be using "long long" here not just "long".  While on Linux etc.
> > > a "long" is 8 bytes, on Windows "long" is only 4 bytes.
> >
> > I was hoping this would not be necessary, and I cannot think of a
> > typical use case where make is a good fit for dealing with large
> > integers. The benefit of "long" is that strtol is more widely
> > available than strtoll.
>
> I see what you mean, but I _really_ don't like the idea of GNU make
> working differently on different platforms, even if such use cases are
> rare.  I can imagine a situation where, for example, someone wants to
> compare the sizes of files and if one of the files is >4G then it will
> work on Linux and fail on Windows.

File sizes are an interesting application indeed. If you want me to
change the patches to use strtoll, I would need some help since I am
not sure how to set things up so that we get a fallback implementation
on platforms where it is missing.