all_options
all_options is a filter on an options object containing all autoloaded options.
Context:
File: wp-includes/functions.php
foreach ($options as $option) {
// "When trying to design a foolproof system,
// never underestimate the ingenuity of the fools :)" -- Dougal
if ('siteurl' == $option->option_name) $option->option_value = preg_replace('|/+$|', '', $option->option_value);
if ('home' == $option->option_name) $option->option_value = preg_replace('|/+$|', '', $option->option_value);
if ('category_base' == $option->option_name) $option->option_value = preg_replace('|/+$|', '', $option->option_value);
@ $value = unserialize($option->option_value);
if ($value === FALSE)
$value = $option->option_value;
$all_options->{$option->option_name} = apply_filters('pre_option_' . $option->option_name, $value);
}
return apply_filters('all_options', $all_options);
This hook is a filter which means that information is passed through it, and then used by WordPress. Your function needs to accept that information, and return it. Using add_filter('all_options', 'your_function'); helps you to remember this distinction. When you are passing an ID, it is assumed that you will return the ID as it was given to you. With filters that pass strings or arrays, you may manipulate the information before passing it along.