wp_unique_id( string $prefix = '' ): string
- Since
- 5.0.3
- Source
wp-includes/functions.php:8156
Description
This is a PHP implementation of Underscore's uniqueId method. A static variable contains an integer that is incremented with each call. This number is returned with the optional prefix. As such the returned value is not universally unique, but it is unique across the life of the PHP process.
Compatibility
- WordPress
- since 5.0.3
- 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
$prefixstringoptional- Prefix for the returned ID.Default:
''
Return value
string- Unique ID.
Performance profile
How much work a call to wp_unique_id() 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
- 5
- Plugin surface
- None
- Called by
- 16
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. The body compiles to 5.
Nothing here hands control to plugin code.
16 places in core call this, so the cost is paid more often than your own code shows.
What one call costs · 1 distinct outcome
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_unique_id() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 5 | none |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 5 instructions, 5 executed per call, 0 branches. The work does not change between versions.
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.
Used by · 16
- WP_Duotone::render_duotone_support()Render out the duotone CSS styles and SVG.
- WP_Navigation_Block_Renderer::get_responsive_container_markup()Get the responsive container markup
- block_core_accordion_item_render()
- block_core_gallery_render()Renders the `core/gallery` block on the server.
- block_core_navigation_add_support_classes_to_container()Adds Navigation block support classes to inner list containers.
- block_core_tabs_provide_context()Filter to provide tabs list context to core/tabs and core/tab-list blocks.
- do_settings_sections()Prints out all settings sections added to a particular settings page.
- render_block_core_archives()Renders the `core/archives` block on server.
- render_block_core_media_text()Renders the `core/media-text` block on server.
- render_block_core_playlist()Renders the `core/playlist` block on server.
- render_block_core_search()Dynamically renders the `core/search` block.
- twentyseventeen_unique_id()Gets unique ID.
Show all 16
- twentytwenty_unique_id()Gets unique ID.
- wp_get_tooltip_helper()Retrieves the markup for an accessible tooltip or toggletip.
- wp_render_block_style_variation_support_styles()Renders the block style variation's styles.
- wp_render_position_support()Renders position styles to the block wrapper.
Source code
function wp_unique_id( $prefix = '' ) { static $id_counter = 0; return $prefix . (string) ++$id_counter;}Changelog
Introduced in 5.0.3. 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/functions.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.