Determines if x is NaN.
a floating point number.
true if x is Nan.
assert( isNaN(float.init)); assert( isNaN(-double.init)); assert( isNaN(real.nan)); assert( isNaN(-real.nan)); assert(!isNaN(cast(float) 53.6)); assert(!isNaN(cast(real)-53.6));
See Implementation
Determines if x is NaN.