Question

I have a simple single threaded Clojure program that creates a temp file for swapping data. When the program exits normally this file is deleted, however when the program is exited via Ctrl+C, Ctrl+D, or Ctrl+Z that bit of code never executes. I need it to execute regardles sof how the program exits. I know that I need to catch that signal (I’ve done this before in other languages), but I can’t seem to figure out how to do it in Clojure.

Answer 1

I don’t know if Clojure has wrapped method for that purpose. In java, you can use Runtime.addShutdownHook()

Registers a new virtual-machine shutdown hook.

The Java virtual machine shuts down in response to two kinds of events:

• The program exits normally, when the last non-daemon thread exits or when the exit (equivalently, System.exit) method is invoked, or

• The virtual machine is terminated in response to a user interrupt, such as typing ^C, or a system-wide event, such as user logoff or system shutdown.

Update

Here is a simple demo

(.addShutdownHook (Runtime/getRuntime) (Thread. (fn [] (println "Shutting down..."))))

user=> ;; Ctrl-C
Shutting down...