Filters the value of an existing option before it is retrieved.

The dynamic portion of the hook name, $option, refers to the option name.

Returning a value other than false from the filter will short-circuit retrieval and return that value instead.

$pre_option mixed

The value to return instead of the option value. This differs from $default, which is used as the fallback value in the event the option doesn't exist elsewhere in get_option() .
Default false (to skip past the short-circuit).

$option string

Option name.

$default mixed

The fallback value to return if the option does not exist.
Default false.

• This hook is used to temporarily alter a WordPress option before the display of a specific view. WordPress options (e.g. the blog configuration) are usually set in the back-end by the user or programmatically by a plugin. The options are stored in the database. To alter the value of an option during the rendering of a page without changing it permanently in the database, you may use this hook.
• Example option name {$option} can the following:
  
pre_option_posts_per_page
pre_option_posts_per_rss
pre_option_template
pre_option_stylesheet
pre_option_blog_charset
pre_option_home
...

• For a list of all available options, call
  wp_load_alloptions()
  which returns the list of available options as an array that you could store in a variable or display for debugging purposes.

File: wp-includes/option.php. View all references

$pre = apply_filters( "pre_option_{$option}", false, $option, $default );