nan constant

A Not-a-Number (NaN) value of type double.

NaN represents the result of a floating-point operation that has no meaningful numeric value, for example double.infinity - double.infinity.

A NaN is not meaningfully comparable to actual values. It compares unequal to every value, including itself, so double.nan == double.nan is false and every ordering comparison with a NaN is false. Test for a NaN with isNaN, never with == double.nan or identical(..., double.nan).

There is more than one NaN value. Any 64 bits define a double value as an IEEE 754 64-bit floating point value, and a significant number of those bit patterns are NaN values. The Dart double type does not make any attempt to distinguish different NaN representations, or promise that any specific one is used. The bit pattern of this value is not stable across platforms or releases, and must not be relied upon.