Re: [Mingw-users] msvcrt printf bug
> But since you don't seem to be encountering such issues yourself with
> modern Linux gcc,
Oops, I'm blushing a bit... but anyway: I actually use a native
_Windows_ port of MinGW. :-D
> I tried the experiment of generating PLplot results [...] using both -O0 and -O3, and indeed the
> results are identical (for 33 standard plplot examples representing
> several hundred pages of plots so it is an extensive test)!
Just excellent! :-)
> So it
> appears the conclusion must be that floating-point calculations are
> done in much more consistent ways now with gcc for both your case and
> this recent PLplot test , and I intend to double-check that
> (unexpected for me) conclusion for the timeephem and FreeEOS projects
> where results are not so heavily rounded as those of PLplot.
Please do, and keep us posted.
> However, for whatever reason (e.g., everyone might now be using the
> same IEEE floating-point calculation algorithms) assuming this
> floating-point consistency is now true for most compilers (so long as
> no optimization is done other than the normal -O0 through -O3
> options), that is an important floating-point breakthrough that would
> make comparisons of results from one compiler to others _much_ simpler
> (as you have already discovered for your software project).
> Furthermore, if care was used to not gratuitously mess with the order
> of computations from one software release to the next, this
> breakthrough should also simplify consistency testing of results for
> various software versions.
Indeed, I find it extremely valuable.
> Finally, to drag this post back on topic for this list, I haven't paid
> much attention to earlier posts in this thread, but assuming from your
> subject line this floating-point consistency is not currently
> available for any unpatched official release of the MinGW version of
> gcc, this inconsistency is something I would strongly encourage the
> MinGW developers to address to aid such important cross-platform
> consistency testing.
Fully agree. Oops (once again!), I actually have no idea whether the
precise MinGW compiler we use is a "patched official release"... but
maybe it is:
gcc (i686-win32-sjlj-rev3, Built by MinGW-W64 project) 4.9.1
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
MinGW-users mailing list
This list observes the Etiquette found at
We ask that you be polite and do the same. Disregard for the list etiquette may cause your account to be moderated.
You may change your MinGW Account Options or unsubscribe at: