IF with a single NaN value returns **true**, but that is **wrong** about basic HOT 3 OPEN

But nanV is not 0. So it can't be false.

from basic.

"But nanV is not 0" that is right.
But the comparison with NaN has to be false by definition.
See the examples below.

Comparison with NaN
A comparison with a NaN always returns an unordered result even when comparing with itself. The
comparison predicates are either signaling or non-signaling on quiet NaN operands; the signaling
versions signal the invalid operation exception for such comparisons. The equality and inequality
predicates are non-signaling so x = x returning false can be used to test if x is a quiet NaN. The other
standard comparison predicates are all signaling if they receive a NaN operand, the standard also
provides non-signaling versions of these other predicates. The predicate isNaN(x) determines if a value
is a NaN and never signals an exception, even if x is a signaling NaN.
Comparison between NaN and any floating-point value x (including NaN and ±∞)
Comparison NaN ≥ x NaN ≤ x NaN > x NaN < x NaN = x NaN ≠ x
Result Always False Always False Always False Always False Always False Always True
See also
https://docs.oracle.com/cd/E19957-01/806-3568/ncg_intro.html#110

But nanV is not 0. So it can't be false.

Thank you very much!
Yes, I have to extend the loop commands.
IF nanV then ?"true" else ?"false"
works like a charm now.

IF nanV = nanV then ?"true" else ?"false"
and
IF nanV = !nanV then ?"true" else ?"false"
returns false as expected, but
IF !nanV = nanV then ?"true" else ?"false"
returns true. So sad!
Any ideas?

from basic.

OK, found a solution now.

from basic.