Re: printf("%.0f", 0.5) and round-to-even

[Eric Blake]

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According to Bruno Haible on 9/30/2008 4:43 AM:
> Does glibc do round-to-even here generally (not just in the one special case
> you mentioned?) If so, the module name should be called fprintf-gnu, otherwise
> fprintf-posix-ext.

Both glibc and the gnulib *printf replacement already round to nearest;
and cygwin 1.5.x failed enough other tests that the gnulib replacement was
already selected (as evidenced by the fact that on cygwin, gawk and m4 got
different results, because only m4 uses gnulib's replacements).

                    glibc  newlib
printf("%.0f",0.5)      0       1
printf("%.0f",1.5)      2       1
printf("%.0f",2.5)      2       2
printf("%.0f",3.5)      4       3
printf("%.0e,0.25)   2e-01  2e-01
printf("%.0e,0.75)   8e-01  7e-01

I suspect %a is also affected, although in newlib's case, %a goes through
a different code path than %[efg].

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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