---
title: lock()
framework: os
role: symbol
role_heading: Instance Method
path: os/osallocatedunfairlock/lock()
---

# lock()

Acquires a lock.

## Declaration

```swift
func lock()
```

## See Also

### Using locks

- [lockIfAvailable()](os/osallocatedunfairlock/lockifavailable().md)
- [unlock()](os/osallocatedunfairlock/unlock().md)