| Re: Generating errors [message #51358 is a reply to message #51357] |
Thu, 16 November 2006 09:13   |
Braedley
Messages: 57
Registered: September 2006
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Member |
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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.
David Fanning wrote:
> Braedley writes:
>
>> Is the any way to generate a generic error if a given condition fails?
>> For example:
>>
>> catch, the_error
>> if the_error ne 0 then begin
>> ;fix what needs to be fixed
>> catch, /cancel
>> return ;so the user can try again
>> endif
>>
>> ;some other code
>>
>> if n ne (*state).m then begin
>> ;do something to notify user
>> ;throw the error
>> endif
>>
>> ;some more code that may generate errors
>>
>>
>> BTW, this is in the event handler of a widget program, and it's assumed
>> that the problem can be fixed before the user tries again.
>> Is there any well defined mechanism to do what I want, or do I have to
>> do something like
>>
>> a=intarr(3)
>> a[4]=0
>>
>> in order to generate my error?
>
> If you are going to fix the error, then you want it fixed
> in THIS module. Don't RETURN out of your error handler code!
> (Unless you plan to fix something that is in the state or
> info structure.) If you don't RETURN, you will run through
> the code again. (The CATCH, /CANCEL in your error handler
> code will prevent you from getting into an infinite loop
> if you don't *completely* fix the problem! :-)
>
> In terms of throwing an error, the MESSAGE command is usually
> used for this purpose. See the document ion for my ERROR_MESSAGE
> program for how to Catch and Throw errors.
>
> Cheers,
>
> David
>
> 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.")
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