On 2011-06-11 01:57, Tom Lane wrote:
(5) Lobby your libc providers to make strtod accept denormals without throwing ERANGE. There is no obvious reason why it shouldn't. (On at least one of my boxes, it does.)
The standard either explicitly allows or requires this behaviour (depending on which text I look at) for underflow.
AIUI that is defined to be a little vague, but includes denormalized numbers that would undergo any rounding at all. It says that on overflow the conversion should return the appropriate HUGE_VAL variant, and set ERANGE. On underflow it returns a reasonably appropriate value (and either may or must set ERANGE, which is the part that isn't clear to me).
ISTM the appropriate response to ERANGE combined with a "small" return value is to either ignore or report the rounding error, but accept the return value. The current code in float.c doesn't check the return value at all and treats all ERANGE conditions as equal.
Jeroen -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
