Title: preview_theme_ob_filter
Published: April 25, 2014
Last modified: April 28, 2025

---

# preview_theme_ob_filter( string $content ): string

## In this article

 * [Parameters](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#changelog)

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

This function has been deprecated since 4.3.0.

This function’s access is marked private. This means it is not intended for use 
by plugin or theme developers, only by core. It is listed here for completeness.

Callback function for ob_start() to capture all links in the theme.

## 󠀁[Parameters](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#parameters)󠁿

 `$content`stringrequired

## 󠀁[Return](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#return)󠁿

 string

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

    ```php
    function preview_theme_ob_filter( $content ) {
    	_deprecated_function( __FUNCTION__, '4.3.0' );
    	return $content;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/deprecated.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/deprecated.php#L3546)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/deprecated.php#L3546-L3549)

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

| Uses | Description | 
| [_deprecated_function()](https://developer.wordpress.org/reference/functions/_deprecated_function/)`wp-includes/functions.php` |

Marks a function as deprecated and inform when it has been used.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/functions/preview_theme_ob_filter/?output_format=md#changelog)󠁿

| Version | Description | 
| [4.3.0](https://developer.wordpress.org/reference/since/4.3.0/) | Deprecated.  | 
| [2.6.0](https://developer.wordpress.org/reference/since/2.6.0/) | Introduced. |

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