[plt-scheme] debugging [mini rant]

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Wed Jul 29 09:20:10 EDT 2009

On Wed, Jul 29, 2009 at 7:50 AM, Mike Eggleston<mikeegg1 at mac.com> wrote:
> On Wed, 29 Jul 2009, Eli Barzilay might have said:
>> On Jul 29, Mike Eggleston wrote:
>> >
>> > Yes, much, and preferable in a production environment when you're
>> > trying to figure out why something is not right. Any change you make
>> > to the code must be tested again, so if you can run the code through
>> > a debugger without changes is best. If you make a change to add
>> > printf()s then you can't say for certain if your printf() caused the
>> > error or if you've found the reported error.
>> This point is bogus.  I personally had one occasion where I had spent
>> about 14 hours chasing a problem that we discovered in a release mode
>> build of our product.  It was there for about a week before that (and
>> it was the segfaulting kind of a problem), yet we didn't know about it
>> because it didn't happen in debug mode.
> Not bogus for me. I perform this type of debugging often on production
> systems. I like to know I have made no changes to a system I'm trying
> to find the error in, that I've not introduced another issue by changing
> the code to add printf()s (stdout or file).

No to belabor the obvious here, but debuggers change the behavior of
your program (perhaps even more than printfs, depending on what you're


Posted on the users mailing list.