Re: "seq .1 .1" would mistakenly generate no output on FreeBSD 6.1

[Paul Eggert]

Come to think of it, aren't the symptoms Jim reported in
<http://lists.gnu.org/archive/html/bug-gnulib/2007-11/msg00131.html>
nearly the opposite of the BeOS symptoms?

If I understand things aright, BeOS incorrectly claimed that
LDBL_MANT_DIG is 53 when it is actually 64.  But FreeBSD has a
different problem.  Its problem is that some long-double operations
use a 53-bit fraction while others use 64 bits.  In the example
program you gave, division converted to a 53-bit fraction, whereas
strtold converted to a 64-bit fraction.

For more details about the quirks of FreeBSD and long double, please see
<http://lists.gnu.org/archive/html/bug-coreutils/2007-11/msg00149.html>
(which talks about the problem with "seq") and
<http://lists.freebsd.org/pipermail/freebsd-standards/2007-September/001449.html>
and
<http://lists.freebsd.org/pipermail/freebsd-standards/2007-October/001450.html>
(which talks about the problem with <float.h> sometimes overestimating
LDBL_MANT_DIG).

One possible workaround is for vasnprintf to use fpsetprec/fesetprec
to undo the FreeBSD hack that forces long double operations to
generate only 53-bit results.