Andrew Dunstan <andrew@dunslane.net> writes:
> Does anyone have a clue why?
Evidently your sscanf isn't setting errno for overflow --- look at
seg_atof() in segparse.y.
This code shows several other signs of severe brain death, actually,
like leaking 256 bytes on each call for an error message buffer that it
doesn't even need :-( I'd recommend ripping the whole thing out and
replacing with a call to float4in.
regards, tom lane