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Re: printf("%.0f", 0.5) and round-to-even
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From: |
Jim Meyering |
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Subject: |
Re: printf("%.0f", 0.5) and round-to-even |
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Date: |
Tue, 30 Sep 2008 11:59:38 +0200 |
Eric Blake <address@hidden> wrote:
> An interesting question popped up on the bug-gnu-utils list:
> http://lists.gnu.org/archive/html/bug-gnu-utils/2008-09/msg00055.html
>
> POSIX states that with %f, the low-order digit is rounded in an
> implementation-
> defined manner. However, since 0.5 is exactly half-way between 0 and 1, and
> most machines default to IEEE round-to-even, should we make the gnulib printf-
> posix check enforce that printf("%.0f", 0.5) outputs "0" per round-to-even
> rules? If so, then at least cygwin 1.5.x fails this check, by outputting "1".
That sounds like the right way to go.