# V3076\. Comparison with 'double\.NaN' is meaningless\. Use 'double\.IsNaN\(\)' method instead\.

The analyzer detected that a variable of type float or double is compared with a float\.NaN or double\.NaN value\. As stated in the documentation, if two double\.NaN values are tested for equality by using the \=\= operator, the result is false\. So, no matter what value of type double is compared with double\.NaN, the result is always false\.

Consider the following example:

```cpp
void Func(double d) {
  if (d == double.NaN) {
    ....
  }
}
```

It's incorrect to test the value for NaN using operators \=\= and \!\=\. Instead, method float\.IsNaN\(\) or double\.IsNaN\(\) should be used\. The fixed version of the code:

```cpp
void Func(double d) {
  if (double.IsNaN(d)) {
    ....
  }
}
```