Title: AtomParser::is_declared_content_ns
Published: April 25, 2014
Last modified: February 24, 2026

---

# AtomParser::is_declared_content_ns( $new_mapping )

## In this article

 * [Source](https://developer.wordpress.org/reference/classes/atomparser/is_declared_content_ns/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/atomparser/is_declared_content_ns/?output_format=md#related)

[ Back to top](https://developer.wordpress.org/reference/classes/atomparser/is_declared_content_ns/?output_format=md#wp--skip-link--target)

## 󠀁[Source](https://developer.wordpress.org/reference/classes/atomparser/is_declared_content_ns/?output_format=md#source)󠁿

    ```php
    function is_declared_content_ns($new_mapping) {
        foreach($this->content_ns_contexts as $context) {
            foreach($context as $mapping) {
                if($new_mapping == $mapping) {
                    return true;
                }
            }
        }
        return false;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/atomlib.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/atomlib.php#L386)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/atomlib.php#L386-L395)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/atomparser/is_declared_content_ns/?output_format=md#related)󠁿

| Used by | Description | 
| [AtomParser::start_element()](https://developer.wordpress.org/reference/classes/atomparser/start_element/)`wp-includes/atomlib.php` |  |

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