---
title: "addConstraint(_:)"
framework: quartzcore
role: symbol
role_heading: Instance Method
path: "quartzcore/calayer/addconstraint(_:)"
---

# addConstraint(_:)

Adds the specified constraint to the layer.

## Declaration

```swift
func addConstraint(_ c: CAConstraint)
```

## Parameters

- `c`: The constraint object to add to the receiver’s array of constraint objects.

## Discussion

Discussion In macOS, you typically add constraints to a layer to manage the size and position of that layer’s sublayers. Before constraints can be applied, you must also assign a CAConstraintLayoutManager object to the layoutManager property of the layer. For more information about managing layer-based constraints, see Core Animation Programming Guide. iOS apps do not support layer-based constraints.

## See Also

### Managing layer constraints

- [constraints](quartzcore/calayer/constraints.md)