How to Create an Exit Message

How to create an exit message

The abort function does this. For example:

abort("Message goes here")

Note: the abort message will be written to STDERR as opposed to puts which will write to STDOUT.

How to throw error and exit with a custom message in python

Calling sys.exit with a string will work. The docs mention this use explicitly:

In particular, sys.exit("some error message") is a quick way to exit a program when an error occurs.

How to exit a programm with an error message and error code in bash?

You can use Use { ...; } instead of (...) to avoid the sub-shell and the problem that causes and to get the result that you want.

Note that a space after the opening { and a semicolon/etc. and a space before the closing } are required for this (where they are optional with ()).

As to why ls || echo && exit doesn't do what you expect the answer is because the || and && operators have the same precedence and are left-associative (see the POSIX spec).

So when the shell sees

ls || echo "Having trouble" && exit 1;

you think it is

ls || { echo "Having trouble" && exit 1; }

but the shell parses it as

{ ls || echo "Having trouble"; } && exit 1;

Or, as the spec puts it:

The operators "&&" and "||" shall have equal precedence and shall be evaluated with left associativity. For example, both of the following commands write solely bar to standard output:

false && echo foo || echo bar

true || echo foo && echo bar

Message Box Dialog at Exit using Tkinter in Python

You can use the protocol method to bind the window deletion with a function.

from tkinter import *
from tkinter import messagebox

def on_close():
    response=messagebox.askyesno('Exit','Are you sure you want to exit?')
    if response:
        root.destroy()

root=Tk()
root.protocol('WM_DELETE_WINDOW',on_close)

root.mainloop()

UPDATE

According to the docs of atexit module

Functions thus registered are automatically executed upon normal interpreter termination.

The function registered was called after the mainloop was destroyed (since nothing proceeds, it marks the end of program). The GUI element that the function tries to destroy doesn't exist anymore, as also stated by the error.

This module is not meant for the use case you trying to achieve, it's usually used for "cleanup" functions that are supposed to perform a task after the program terminates.

The callback registered via the WM_DELETE_WINDOW protocol gives you the control over what happens when the window is instructed to close.

How to programmatically exit from a second message loop?

You should pass the Form instance to the ApplicationContext ctor as a parameter:

applicationContext = new ApplicationContext(form); 

Right now, you are basically creating a no-context instance, which doesn't care about your form being closed.

Also, it is a good practice to do some cleanup, like removing the filter when you don't need it anymore:

Form form = new Form();
ApplicationContext applicationContext = new ApplicationContext(form);
handleHelper(form.Handle);

MessageFilter filter = new MessageFilter(filter);
Application.AddMessageFilter(filter);
Application.Run(applicationContext);
Application.RemoveMessageFilter(filter);

[Edit]

If you don't want to show the form, then you can use the paramaterless ctor, but you will have to close the context manually by calling the ApplicationContext.ExitThread method. This method actually gets called when your form fires the FormClosed event, if you pass the form in the constructor.

Since hidden form is not related to the context, you need to exit them both at some time.

how to show the popup message on Exit button

JavaScript:

<input type="button" value="Exit" onclick="confirmBox()" />

function confirmBox(){
  if (confirm('Are you sure you want to Exit?')){
    window.location.href = '../index'
  }
}

jQuery:

<input type="button" value="Exit" id="exit" />

$('#exit').click(function(){
   if (confirm('Are you sure you want to Exit?')){
     window.location.href = '../index'
   }
});

How do I show a message before system.exit in Java

I would use the YES_NO_CANCEL_OPTION:

Object[] options = {"Yes","No","Cancel"};
int n = JOptionPane.showOptionDialog(frame,
        "Continue?",
        "Would you like to continue?",
        JOptionPane.YES_NO_CANCEL_OPTION,
        JOptionPane.QUESTION_MESSAGE,
        null,
        options,
        options[2]);
if (n == JOptionPane.YES_OPTION) {
    System.out.println("Clicked Yes");
} else if (n == JOptionPane.NO_OPTION) {
    System.out.println("Clicked No");
} else if (n == JOptionPane.CANCEL_OPTION) {
    System.out.println("Clicked Cancel");
} else {
    System.out.println("something else (like clicked the 'x' button)");
}

exit with error message in bash (oneline)

exit doesn't take more than one argument. To print any message like you want, you can use echo and then exit.

    [[ $TRESHOLD =~ ^[0-9]+$ ]] || \
     { echo "Threshold must be an integer value!"; exit $ERRCODE; }

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