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

On Sat, Feb 7, 2015 at 2:31 PM, Joachim Schmitz [off-list ref] wrote:

Junio C Hamano <gitster <at> pobox.com> writes:

quoted

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,

quoted

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

No, not like that. If you do (1), that is only so that the Makefile can override
a broken definition a platform may give to SSIZE_MAX.  So

 (1) if Makefile gives one, use it without second-guessing with SSIZE_MAX.
 (2) if SSIZE_MAX is defined, and if it is smaller than our internal
default, use it.
 (3) all other cases, us our internal default.