On 10-Sep-2002 John Klein wrote:
> I have a question about obtaining a backtrace when
> catching errors.
>
> consider the following snippet of code:
>
> ;;;;;;;;;;;;;;;;;;;
> (defun top ()
> (multiple-value-bind (ret err) (ignore-errors (foo))
> (when err (format t "Got error <~A>~%" err))
> ;; HERE
> ret))
>
> (defun foo () (bar 0))
> (defun bar (x) (/ 1 x)) ;; bar causes an error for x=0
> ;;;;;;;;;;;;;;;;;;;
>
> This catches and prints a division by 0 error when (top)
> is evaluated.
>
> But is there some way to obtain a backtrace leading to
> the error (eg, to a string) at the location denoted by "HERE"?
> This would be very useful for diagnosing infrequent errors
> in server apps, eg.
It will not work with ignore-errors, but CL has better methods for this.
If you do handler-bind, a function is invoked for the error with all the
stack when it occurs. In this method you should be able to collect the
stacktrace, and then to invoke a restart.
Martin
--
+-[Martin Ginkel]--------------[mailto:ginkel(at)mpi-magdeburg.mpg.de]-+
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