| Re: Generating errors [message #51357 is a reply to message #51355] |
Thu, 16 November 2006 09:27   |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Braedley writes:
> The error would be in the state structure, and would be due to it not
> being updated properly after some other error (that I still have to
> devise a runtime fix for). The thing is that both n and (*state).m
> both become useless for performing the action that the user wanted to
> perform after the problem was fixed. In all likelihood, the original
> value of (*state).m is different from what it should have been, and it
> then becomes impossible to retrieve the value that it should have been
> with 100% accuracy before the fix is implemented. Since I don't want
> to perform an action on (*state).m (that is not easy to undo) without
> being sure that it's the action that the user wants, I'm forced to
> return after the problem is fixed for future use.
Huh? Not sure I'm following everything here... Too many
fingers pointing in too many directions, I guess.
In most of the widget programs I've ever written, the
user can get himself out of it, if the widget program
just keeps running. That is to say, there is *usually*
some way the user can fix the problem for themselves.
So, I usually just tell the user what the problem was,
and keep the program alive for them to figure out the
solution. An error handler like this usually works
well for me:
Catch, theError
IF theError NE 0 THEN BEGIN
Catch, /Cancel
void = Error_Message()
; Whatever clean-up is needed in THIS module. For
; example, put the info structure back in TLB, etc.
RETURN
ENDIF
If you have errors that you *can't* recover from (this is
what your explanation seems to imply to me), then I think
you are basically hosed. Destroy your TLB and start over. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
