Re: read() MAX_IO_SIZE bytes, more than SSIZE_MAX?

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

On Sat, Feb 7, 2015 at 12:32 PM, Torsten Bögershausen <tboegi@web.de> wrote:
> I don't know every platform of the planet well enough to be helpful here,
> especially the ones which don't follow all the specifications.
>
> In other words: As long as we can not guarantee that SSIZE_MAX is defined,
> (and is defined to somethong useful for xread()/xwrite() )
> we should be more defensive here:
>
> tweak only on platform where we know it is needed and we know that it works.

Yup, I agree that is a sensible way to go.

 (1) if Makefile overrides the size, use it; otherwise
 (2) if SSIZE_MAX is defined, and it is smaller than our internal
default, use it; otherwise
 (3) use our internal default.

And leave our internal default to 8MB.

That way, nobody needs to do anything differently from his current build set-up,
and I suspect that it would make step (1) optional.