Unlike the reserve_confirmation hook that runs at the exact time the reserve confirmation email is sent, this hook fires after the reservation confirmation is sent. It is directly after reserve_confirmation.
/**
* @param $inventory_id
* @param $data
* @param $subject
* @param $message
*/
function my_custom_function($inventory_id, $data, $subject, $message) {
// As an example how to get the item info, you could do the following...
$item_info = new WPIMItem(); // Call new instance of WPIMItem class
$item_info = $item_info->get( $inventory_id ); // Get the item information with inventory id
$name = $item_info->inventory_name; // Example of how you would get the name of an item
// Do whatever you want from here!
}
add_action('wpim_reserve_confirmation_sent', 'my_custom_function', 10, 4);