---
title: "addUserDefinedHeader(_:length:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/nsmutabledictionary/adduserdefinedheader(_:length:)"
---

# addUserDefinedHeader(_:length:)

## Declaration

```swift
func addUserDefinedHeader(_ inHeaderData: UnsafeRawPointer!, length inHeaderDataLength: UInt32) -> OBEXError
```