WordPress Version: 6.1
/**
* Updates user meta field based on user ID.
*
* Use the $prev_value parameter to differentiate between meta fields with the
* same key and user ID.
*
* If the meta field for the user does not exist, it will be added.
*
* @since 3.0.0
*
* @link https://developer.wordpress.org/reference/functions/update_user_meta/
*
* @param int $user_id User ID.
* @param string $meta_key Metadata key.
* @param mixed $meta_value Metadata value. Must be serializable if non-scalar.
* @param mixed $prev_value Optional. Previous value to check before updating.
* If specified, only update existing metadata entries with
* this value. Otherwise, update all entries. Default empty.
* @return int|bool Meta ID if the key didn't exist, true on successful update,
* false on failure or if the value passed to the function
* is the same as the one that is already in the database.
*/
function update_user_meta($user_id, $meta_key, $meta_value, $prev_value = '')
{
return update_metadata('user', $user_id, $meta_key, $meta_value, $prev_value);
}