---
title: "isnan(_:)"
framework: simd
role: symbol
role_heading: Function
path: "simd/isnan(_:)-9irpc"
---

# isnan(_:)

Returns true for each element that is not a number (NaN) in a vector.

## Declaration

```swift
func isnan(_ x: simd_double2) -> simd_long2
```

## See Also

### Classification Functions

- [isfinite(_:)](simd/isfinite(_:)-7d8q7.md)
- [isinf(_:)](simd/isinf(_:)-4wflm.md)
- [isnormal(_:)](simd/isnormal(_:)-61nr1.md)