How can we get save event at Photoshop shutdown?

Hi All!!

I have to perform some actions on the save event of a document. I had no problem in doing the same. But, during testing different save event trigger scenarios, I came across the a situation in which an untitled document is open and the user closes Photoshop. At this point Photoshop prompts the "Do you want to save document?" message. Regardless of the user selection ("Yes"/"No"), the plugin is unable to get the save event, possibly because of application shutdown. I get the kSPInterfaceShutdownSelector message directly. No stop at the save event callback.

How can I ensure that my save event callback is executed everytime a user saves a document?

Thanks!