Re: [PATCH 1/3] compat: add qsort_s()

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> To make matters more fun, apparently[1] there are multiple variants of
> qsort_r with different argument orders. _And_ apparently Microsoft
> defines qsort_s, but it's not quite the same thing. But all of that can
> be dealt with by having more specific flags (HAVE_GNU_QSORT_R, etc).
>
> It just seems like we should be able to do a better job of using the
> system qsort in many cases.

If we were to go that route, perhaps we shouldn't have HAVE_QSORT_S
so that Microsoft folks won't define it by mistake (instead perhaps
call it HAVE_ISO_QSORT_S or something).

I like your suggestion in general.  The body of git_qsort_s() on
systems without ISO_QSORT_S can do 

 - GNU qsort_r() without any change in the parameters, 

 - Microsoft qsort_s() with parameter reordered, or 

 - Apple/BSD qsort_r() with parameter reordered.

and that would cover the major platforms.

Eh, wait.  BSD and Microsoft have paramters reordered in the
callback comparison function.  I suspect that would not fly very
well.