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

From
Joachim Schmitz <jojo@schmitz-digital.de>
Date
Feb 7, 2015, 22:31 UTC
Message-ID
<loom.20150207T232422-706@post.gmane.org>
In-Reply-To
<CAPc5daUnKcktv0xcz-fGEApckbkQksKuZO53ZL20E1MhtZmn4w@mail.gmail.com>
Junio C Hamano <gitster <at> pobox.com> writes:
> 
> On Sat, Feb 7, 2015 at 12:32 PM, Torsten Bögershausen <tboegi <at> 
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.
Show 11 quoted lines
> 
> 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.
> 
something like this:

/* allow overwriting from e.g. Makefile */ #if !defined(MAX_IO_SIZE) # define MAX_IO_SIZE (8*1024*1024) #endif /* for plattforms that have SSIZE and have it smaller */ #if defined(SSIZE_MAX && (SSIZE_MAX < MAX_IO_SIZE) # undef MAX_IO_SIZE /* avoid warning */ # define MAX_IO_SIZE SSIZE_MAX #endif

Steps 2 and 3 only , indeed step 1 not needed...
Bye, Jojo
Previous: Junio C HamanoNext: Junio C Hamano
Message 8 of 20 in “read() MAX_IO_SIZE bytes, more than SSIZE_MAX?”
  1. Joachim SchmitzFeb 7, 2015
  2. Joachim SchmitzFeb 7, 2015
  3. Torsten BögershausenFeb 7, 2015
  4. Joachim SchmitzFeb 7, 2015
  5. Joachim SchmitzFeb 7, 2015
  6. Torsten BögershausenFeb 7, 2015
  7. Junio C HamanoFeb 7, 2015
  8. Joachim SchmitzFeb 7, 2015
  9. Junio C HamanoFeb 8, 2015
  10. Randall S. BeckerFeb 8, 2015
  11. Joachim SchmitzFeb 8, 2015
  12. Eric SunshineFeb 8, 2015
  13. Junio C HamanoFeb 11, 2015
  14. Joachim SchmitzFeb 11, 2015
  15. Joachim SchmitzFeb 11, 2015
  16. Junio C HamanoFeb 11, 2015
  17. Randall S. BeckerFeb 7, 2015
  18. Randall S. BeckerFeb 7, 2015
  19. Joachim SchmitzFeb 7, 2015
  20. Joachim SchmitzFeb 7, 2015

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