At Wed, 13 Mar 2019 23:18:27 -0400, Tom Lane <tgl@sss.pgh.pa.us> wrote in <2503.1552533507@sss.pgh.pa.us>
tgl> Andrew Dunstan <andrew.dunstan@2ndquadrant.com> writes:
tgl> > Or we could possibly call the function and then turn a result of -0 into 0?
tgl>
tgl> But -0 is the correct output if the input is -0. So that approach
tgl> requires distinguishing -0 from 0, which is annoyingly difficult.
I think just turning both of -0 and +0 into +0 works, and, FWIW,
it is what is done in geo_ops.c (e.g. line_construct()) as a kind
of normalization and I think it is legit for geo_ops, but I don't
think so for fundamental functions like (d)asinh().
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center