This function had been marked as deprecated since 3.0.0. Use register_setting()

Register a setting and its sanitization callback

Signature

add_option_update_handler( $option_group, $option_name, $sanitize_callback = '' )
option_group
 (string) A settings group name. Should correspond to a whitelisted option key name. Default whitelisted option key names include "general," "discussion," and "reading," among others.
option_name
 (string) The name of an option to sanitize and save.
sanitize_callback
 (unknown_type) A callback function that sanitizes the option's value.
Default: ''

Return

(unknown)

Source

function add_option_update_handler( $option_group, $option_name, $sanitize_callback = '' ) {
	_deprecated_function( __FUNCTION__, '3.0', 'register_setting()' );
	return register_setting( $option_group, $option_name, $sanitize_callback );
}
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