nag_is_nan (x07abc) determines whether a floating-point number is a NaN (Not A Number).
nag_is_nan (x07abc) returns Nag_TRUE if and only if
x is a NaN, and returns Nag_FALSE otherwise.
None.
Not applicable.
Not applicable.
None.
See
Section 10 in nag_is_finite (x07aac).