How to catch CTRL+C in Clojure?
Asked Answered
L

2

17

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.

Landwehr answered 29/7, 2012 at 13:32 Comment(1)
It would be very interesting to find out if there's a native Clojure solution. I'm assuming this problem has to do with console applications, not GUI, like Seesaw.Kinetic
C
32

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...
Constellation answered 29/7, 2012 at 13:59 Comment(0)
A
1

Have a look at the deleteOnExit method in the java.io.File:

(import '(java.io File))
(doto (File/createTempFile "foo" nil nil) (.deleteOnExit))
Autopsy answered 29/7, 2012 at 22:1 Comment(0)

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