add_shortcode( string $tag, callable $callback )

Adds a new shortcode.

Description

Care should be taken through prefixing or other means to ensure that the shortcode tag being added is unique and will not conflict with other, already-added shortcode tags. In the event of a duplicated tag, the tag loaded last will take precedence.

Parameters

$tag

(string) (Required) Shortcode tag to be searched in post content.

$callback

(callable) (Required) The callback function to run when the shortcode is found. Every shortcode callback is passed three parameters by default, including an array of attributes ($atts), the shortcode content or null if not set ($content), and finally the shortcode tag itself ($shortcode_tag), in that order.

More Information

The shortcode callback will be passed three arguments: the shortcode attributes, the shortcode content (if any), and the name of the shortcode.

There can only be one hook for each shortcode. This means that if another plugin has a similar shortcode, it will override yours, or yours will override theirs depending on which order the plugins are included and/or ran.

Shortcode attribute names are always converted to lowercase before they are passed into the handler function. Values are untouched.

Note that the function called by the shortcode should never produce an output of any kind. Shortcode functions should return the text that is to be used to replace the shortcode. Producing the output directly will lead to unexpected results. This is similar to the way filter functions should behave, in that they should not produce unexpected side effects from the call since you cannot control when and where they are called from.

Source

File: wp-includes/shortcodes.php 

function add_shortcode( $tag, $callback ) {
	global $shortcode_tags;

	if ( '' === trim( $tag ) ) {
		_doing_it_wrong(
			__FUNCTION__,
			__( 'Invalid shortcode name: Empty name given.' ),
			'4.4.0'
		);
		return;
	}

	if ( 0 !== preg_match( '@[<>&/\[\]\x00-\x20=]@', $tag ) ) {
		_doing_it_wrong(
			__FUNCTION__,
			sprintf(
				/* translators: 1: Shortcode name, 2: Space-separated list of reserved characters. */
				__( 'Invalid shortcode name: %1$s. Do not use spaces or reserved characters: %2$s' ),
				$tag,
				'& / < > [ ] ='
			),
			'4.4.0'
		);
		return;
	}

	$shortcode_tags[ $tag ] = $callback;
}

Uses

Uses Description
wp-includes/l10n.php: __()

Retrieve the translation of $text.
wp-includes/functions.php: _doing_it_wrong()

Mark something as being incorrectly called.

Changelog

Version Description
2.5.0 Introduced.

© 2003–2021 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/add_shortcode