---
title: HeaderNamesRange
summary: Iterates over all header names in a request or response.
url: https://www.fastly.com/documentation/reference/compute/sdks/cpp/fastly/http/class.HeaderNamesRange/
---

**Kind:** Class  
**Module:** [http](https://www.fastly.com/documentation/reference/compute/sdks/cpp/fastly/http/)  
**Package:** compute-sdk-cpp 0.7.0  
**Source:** https://github.com/fastly/compute-sdk-cpp/blob/ff911e47be2f319e83a9cde960d2c3c5db534280/include/fastly/http/header.h#L94

Include `fastly/http/header.h` to use this class.

Extends `fastly::detail::RustIteratorRange<HeaderNamesRange, fastly::sys::http::HeaderNamesIter>`.

Iterates over all header names in a request or response.

## Methods

### next

**Source:** https://github.com/fastly/compute-sdk-cpp/blob/ff911e47be2f319e83a9cde960d2c3c5db534280/include/fastly/http/header.h#L102

```cpp
std::optional<std::string> fastly::http::HeaderNamesRange::next()
```

Gets the next header name.

**Returns**

`std::optional<std::string>`