---
title: "+=(_:_:)"
framework: simd
role: symbol
role_heading: Operator
path: "simd/simd_quatf/+=(_:_:)"
---

# +=(_:_:)

Adds two quaternions and stores the result in the left-hand-side variable.

## Declaration

```swift
static func += (lhs: inout simd_quatf, rhs: simd_quatf)
```