---
layout: docs
title: buildDeclaration
id: class.Facebook.HackCodegen.CodegenInterface.buildDeclaration
docid: class.Facebook.HackCodegen.CodegenInterface.buildDeclaration
permalink: /docs/reference/class.Facebook.HackCodegen.CodegenInterface.buildDeclaration/
---
# Facebook\\HackCodegen\\CodegenInterface::buildDeclaration()




``` Hack
protected function buildDeclaration(
  Facebook\HackCodegen\HackBuilder $builder,
): void;
```




## Parameters




+ [` Facebook\HackCodegen\HackBuilder `](<class.Facebook.HackCodegen.HackBuilder.md>)`` $builder ``




## Returns




* ` void `