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

---

# logIO( string $io, string $msg )

## In this article

 * [Description](https://developer.wordpress.org/reference/functions/logio/?output_format=md#description)
    - [See also](https://developer.wordpress.org/reference/functions/logio/?output_format=md#see-also)
 * [Parameters](https://developer.wordpress.org/reference/functions/logio/?output_format=md#parameters)
 * [Source](https://developer.wordpress.org/reference/functions/logio/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/functions/logio/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/functions/logio/?output_format=md#changelog)

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

This function has been deprecated since 3.4.0. Use [error_log()](https://www.php.net/manual/en/function.error-log.php/)
instead.

[logIO()](https://developer.wordpress.org/reference/functions/logio/) – Writes logging
info to a file.

## 󠀁[Description](https://developer.wordpress.org/reference/functions/logio/?output_format=md#description)󠁿

### 󠀁[See also](https://developer.wordpress.org/reference/functions/logio/?output_format=md#see-also)󠁿

 * [error_log()](https://www.php.net/manual/en/function.error-log.php/)

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

 `$io`stringrequired

Whether input or output.

`$msg`stringrequired

Information describing logging reason.

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

    ```php
    function logIO( $io, $msg ) {
    	_deprecated_function( __FUNCTION__, '3.4.0', 'error_log()' );
    	if ( ! empty( $GLOBALS['xmlrpc_logging'] ) ) {
    		error_log( $io . ' - ' . $msg );
    	}
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/xmlrpc.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/xmlrpc.php#L101)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/xmlrpc.php#L101-L106)

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

| Version | Description | 
| [3.4.0](https://developer.wordpress.org/reference/since/3.4.0/) | Deprecated. Use error_log() | 
| [1.2.0](https://developer.wordpress.org/reference/since/1.2.0/) | Introduced. |

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