add_shortcode( string $tag, callable $callback )
- Since
- 2.5.0
- Source
wp-includes/shortcodes.php:63
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.
Compatibility
- WordPress
- since 2.5.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$tagstring- Shortcode tag to be searched in post content.
$callbackcallable- The callback function to run when the shortcode is found.
Every shortcode callback is passed three parameters by default, including an array of attributes ($atts), the shortcode content or null if not set ($content), and finally the shortcode tag itself ($shortcode_tag), in that order.
Performance profile
How much work a call to add_shortcode() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Trivial
- Scaling
- Constant
- Instructions
- 12–23
- Plugin surface
- None
- Called by
- 2
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 35.
Nothing here hands control to plugin code.
2 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
do_action()one call below add_shortcode()
Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost add_shortcode() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 12 | none |
| always | 15 | __(), _doing_it_wrong() |
| always | 23 | __(), sprintf(), _doing_it_wrong() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 35 | 12–23 | 2 | |
| 8.5 | 35 | 12–23 | 2 | |
| 8.4 | 35 | 12–23 | 2 | 5 fewer instructions than PHP 8.3 |
| 8.3 | 40 | 17–28 | 2 | |
| 8.2 | 40 | 17–28 | 2 | |
| 8.1 | 40 | 17–28 | 2 | |
| 7.4 | 40 | 17–28 | 2 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 2
- _doing_it_wrong()Marks something as being incorrectly called.
- __()Retrieves the translation of $text.
Used by · 2
- WP_Embed::__construct()Constructor
- WP_Embed::run_shortcode()Processes the [embed] shortcode.
Source code
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;}Changelog
Introduced in 2.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/shortcodes.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.