Thinking about this more, you ask "is this correct", but that
is only meaningful if you say what the specification is.
Correct relative to what?
> Yes, it seems to be the correct way, but thinking more about the
> problem, it appeared to me that the implementation could be even easier
> than yours. It seems to me that this may be sufficient:
> uint64_t float64_to_uint64 (float64 a STATUS_PARAM)
> {
> int64_t v;
>
> v = llrint(a + (float64)INT64_MIN);
>
> return v - INT64_MIN;
> }
If a is NaN then so is the argument to llrint. 'man llrint' says:
If x is infinite or NaN, or if the rounded value is
outside the range of the return type, the numeric result
is unspecified.
So then float64_to_uint64 produces an unspecified result.
It seems to me much safer to test and handle NaN, Inf and
out-of-range values specially. However, even that does not help
unless you say what the specification is.
J
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