▼ |  | Framework: Racket GUI Application Framework

1 | Application
2 | Autosave
3 | Canvas
4 | Color Model
5 | Color Prefs
6 | Color
7 | Comment Box
8 | Editor Snip
9 | Editor
10 | Exit
11 | Finder
12 | Frame
13 | Group
14 | GUI Utilities
15 | Handler
16 | Icon
17 | Keymap
18 | Menu
19 | Mode
20 | Number Snip
21 | Panel
22 | Pasteboard
23 | Path Utils
24 | Preferences
25 | Preferences, Textual
26 | Racket
27 | Text
28 | Splash
29 | Test
30 | Version
| Index

On this page:

exit: exiting?
exit: set-exiting
exit: insert-on-callback
exit: insert-can?-callback
exit: can-exit?
exit: on-exit
exit: exit
exit: user-oks-exit

top ← prev up next →

### 10`` Exit

( exit:exiting? ) → boolean?

Returns #t to indicate that an exit operation is taking place. Does not indicate that the app will actually exit, since the user may cancel the exit.

See also exit:insert-on-callback and exit:insert-can?-callback.

( exit:set-exiting exiting?) → void?
exiting? : boolean?

Sets a flag that affects the result of exit:exiting?.

( exit:insert-on-callback callback) → ( -> void? )
callback : ( -> void? )

Adds a callback to be called when exiting. This callback must not fail. If a callback should stop an exit from happening, use exit:insert-can?-callback.

( exit:insert-can?-callback callback) → ( -> void? )
callback : ( -> boolean? )

Use this function to add a callback that determines if an attempted exit can proceed. This callback should not clean up any state, since another callback may veto the exit. Use exit:insert-on-callback for callbacks that clean up state.

( exit:can-exit? ) → boolean?

Calls the “can-callbacks” and returns their results. See exit:insert-can?-callback for more information.

( exit:on-exit ) → void?

Calls the “on-callbacks”. See exit:insert-on-callback for more information.

( exit:exit ) → any

exit:exit performs four actions:

- sets the result of the exit:exiting? function to #t.

- invokes the exit-callbacks, with exit:can-exit? if none of the “can?” callbacks return #f,

- invokes exit:on-exit and then

- queues a callback that calls exit (a racket procedure) and (if exit returns) sets the result of exit:exiting? back to #t.

( exit:user-oks-exit ) → boolean?

Opens a dialog that queries the user about exiting. Returns the user’s decision.
top ← prev up next →