## Function: SB-EXT:LOCK-PACKAGE
[![package](https://img.shields.io/badge/Package-SB--EXT-5f9ea0.svg?style=social&colorA=999999)](../) [![type](https://img.shields.io/badge/Type-Function-5f9ea0.svg?style=social&colorA=999999)](../#function) [![github](https://img.shields.io/badge/GitHub-View_the_source-5f9ea0.svg?style=social&colorA=999999&logo=github)](https://github.com/sbcl/sbcl/blob/master/src/code/target-package.lisp/) 

> Locks PACKAGE and returns T. Has no effect if PACKAGE was already
> locked. Signals an error if PACKAGE is not a valid package designator

### Lambda list
```cl
(package)
```