Thanks for the explanation, that's exactly the level of detail I need.
-Robert
On Tue, Apr 21, 2009 at 12:00 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Robert Morton <morton2002@gmail.com> writes: > Perhaps there are platform differences, since the version I am using was > built with Microsoft Visual Studio:
Ah, now you tell us.
round(float8) just calls the platform's rint() function. At least on platforms that have rint(), which maybe Windows doesn't. In that case it's going to come down to src/port/rint.c, which is not particularly careful about the exactly-0.5 case. I think fully-standards-conformant versions of rint() are probably going to use a "round to nearest even integer" rule in such cases. But by and large, float8 arithmetic *is* going to have platform-specific behaviors; you're living in a fantasy world if you think otherwise.
