newbie: why it does not work: command=sys.exit?

I have got a problem with een example from the book "Programming Python" -
Mark Lutz
I do not understand why it not work for Windows XP and Linux (Fedora Core
1.0).
Exactly the same problem was raised by DrPhil:
http://coderforums.com/showthread.ph...oto=nextoldest

import sys
from Tkinter import *
widget = Button(None, text='Hello widget world', command = sys.exit)
widget.pack()
widget.mainloop()
----------------------------------------------------------------------------
--------
Traceback (most recent call last):
File "I:\Python\Projecten\#Prog_in_Python\Hfst06\gui02. py", line 5,
in -toplevel-
widget.mainloop()
File "D:\Python23\lib\lib-tk\Tkinter.py", line 965, in mainloop
self.tk.mainloop(n)
File "D:\Python23\lib\lib-tk\Tkinter.py", line 1347, in __call__
raise SystemExit, msg
SystemExit

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At 2004-05-23T22:54:53Z, "Paul van Dam" <> writes:
> import sys
> widget = Button(None, text='Hello widget world', command = sys.exit)


> Traceback (most recent call last):
> File "I:\Python\Projecten\#Prog_in_Python\Hfst06\gui02. py", line 5,
> in -toplevel-
> widget.mainloop()
> File "D:\Python23\lib\lib-tk\Tkinter.py", line 965, in mainloop
> self.tk.mainloop(n)
> File "D:\Python23\lib\lib-tk\Tkinter.py", line 1347, in __call__
> raise SystemExit, msg
> SystemExit

- From "pydoc sys.exit"

Help on built-in function exit in sys:

sys.exit = exit(...)
exit([status])

Exit the interpreter by raising SystemExit(status). If the status
is omitted or None, it defaults to zero (i.e., success). If the
status is numeric, it will be used as the system exit status. If it
is another kind of object, it will be printed and the system exit
status will be one (i.e., failure).

The documentation says that calling sys.exit raises a SystemExit exception.
Your program calls sys.exit and gets a SystemExit exception. It seems to be
working as expected and documented, unless I'm missing something.
- --
Kirk Strauser
The Strauser Group
Open. Solutions. Simple.
http://www.strausergroup.com/
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On Mon, 24 May 2004 00:54:53 +0200, "Paul van Dam"
<> wrote:
> I have got a problem with een example from the book "Programming Python" -
> Mark Lutz
> I do not understand why it not work for Windows XP and Linux (Fedora Core
> 1.0).

> import sys
> from Tkinter import *
> widget = Button(None, text='Hello widget world', command = sys.exit)
> widget.pack()
> widget.mainloop()
> ----------------------------------------------------------------------------
> --------
> Traceback (most recent call last):
> File "I:\Python\Projecten\#Prog_in_Python\Hfst06\gui02. py", line 5,
> in -toplevel-
> widget.mainloop()
> File "D:\Python23\lib\lib-tk\Tkinter.py", line 965, in mainloop
> self.tk.mainloop(n)
> File "D:\Python23\lib\lib-tk\Tkinter.py", line 1347, in __call__
> raise SystemExit, msg
> SystemExit

It is working, its raising SystemExit. The environment that you
are running it in (Either Pythonwin or IDLE?) is catching
SystemExit and displaying the message rather than actually exit -
because it would be a pain having to restart IDLE everytime you
ran the program. But if you run your program from Explorer as
normal then it should exit just fine.

Remember that Pythonwin and IDLE are development tools they are
not the normal place to run programs. Because of that they
sometimes behave a little differently in an attempt to make life
easier for you while developing a program.

HTH,

Alan G
Author of the Learn to Program website
http://www.freenetpages.co.uk/hp/alan.gauld