get_blog_option( int $id, string $option, mixed $default_value = false ): mixed
- Since
- MU (3.0.0)
- Source
wp-includes/ms-blogs.php:357
Description
If the option does not exist or does not have a value, then the return value will be false. This is useful to check whether you need to install an option and is commonly used during installation of plugin options and to test whether upgrading is required.
If the option was serialized then it will be unserialized when it is returned.
Compatibility
- WordPress
- since MU (3.0.0)
- 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
$idint- A blog ID. Can be null to refer to the current blog.
$optionstring- Name of option to retrieve. Expected to not be SQL-escaped.
$default_valuemixedoptional- Default value to return if the option does not exist.Default:
false
Return value
mixed- Value set for the option.
Performance profile
How much work a call to get_blog_option() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Moderate
- Scaling
- Constant
- Instructions
- 16–31
- Plugin surface
- 1 hook
- Called by
- 7
Reads stored settings via get_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 36.
Third-party callbacks on 'blog_option_{$option}' run inside this call, and their cost is not bounded by anything here.
7 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- optionoption read or write
get_option()called directly - hookthird-party callbacks
apply_filters()called directly - cacheobject cache
wp_cache_get()one call below get_blog_option() - serializeserialisation
maybe_unserialize()one call below get_blog_option()
Further down the call graph this can also reach query 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 · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost get_blog_option() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
!empty($id) && $id === false | 16 | get_current_blog_id(), get_option() |
empty($id) && $id === false | 19 | get_current_blog_id(), get_current_blog_id(), get_option() |
!empty($id) && $id !== false | 28 | get_current_blog_id(), switch_to_blog(), get_option(), restore_current_blog(), apply_filters() |
empty($id) && $id !== false | 31 | get_current_blog_id(), get_current_blog_id(), switch_to_blog(), get_option(), restore_current_blog(), apply_filters() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 36 instructions, 16–31 executed per call, 2 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 1
One hook fires while get_blog_option() runs, in this order:
- apply_filters( blog_option_{$option} )filterline 382 (+25 into the body)
Filters a blog option value.
Uses · 5
- get_current_blog_id()Retrieves the current site ID.
- get_option()Retrieves an option value based on an option name.
- switch_to_blog()Switches the current blog.
- restore_current_blog()Restores the current blog, after calling switch_to_blog().
- apply_filters()Calls the callback functions that have been added to a filter hook.
Used by · 7
- WP_MS_Sites_List_Table::get_primary_column_aria_label()Returns a clean label for the primary (URL) column's row header `aria-label`.
- WP_MS_Themes_List_Table::single_row_columns()Handles the output for a single table row.
- WP_Roles::get_roles_data()Gets the available roles data.
- get_rest_url()Retrieves the URL to a REST endpoint on a site.
- install_blog()Install an empty blog.
- wp_initialize_site()Runs the initialization routine for a given site.
- wpmu_new_site_admin_notification()Notifies the Multisite network administrator that a new site was created.
Source code
function get_blog_option( $id, $option, $default_value = false ) { $id = (int) $id; if ( empty( $id ) ) { $id = get_current_blog_id(); } if ( get_current_blog_id() === $id ) { return get_option( $option, $default_value ); } switch_to_blog( $id ); $value = get_option( $option, $default_value ); restore_current_blog(); /** * Filters a blog option value. * * The dynamic portion of the hook name, `$option`, refers to the blog option name. * * @since 3.5.0 * * @param string $value The option value. * @param int $id Blog ID. */ return apply_filters( "blog_option_{$option}", $value, $id );}Changelog
Introduced in MU (3.0.0). 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/ms-blogs.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.