isNaN function

This function returns true if its argument is the special not-a-number floating-point value NAN. Together with isInf, you can use isNaN to check if a floating-point value is still normal, which indicates that all previous operations on it were successful.

Examples:

float x = 1 / 0
print(x)         ; Prints INF
x = x - x
print(x)         ; Prints NAN
print(x < 100)   ; Prints true, but the values are not ordered
print(isNaN(x))  ; Prints true

See Also
isInf function