Re: LYNX-DEV FIX: debugging that URL...

[Foteos Macrides]

address@hidden (Jason Baker) wrote:
>> Filip M Gieszczykiewicz <address@hidden> wrote:
>> >Greetings. Add the following line right before the for (..)
>> >on line 37 of the WWW/Library/Implementation/HTString.c:
>> >
>> >    if (!p) return -1;
>> >
>> >Now it won't dump when it hits URL:
>> >
>> >http://www.safetycare.com.au/mig.html
>> >
>> >and the likes of it.
>> 
>>      That function is called from a zillion places, and should never
>> be called without valid pointers.  If you block the crash there, you'll
>> just mask the real programming error.
>
>Just a thought - what about putting something like (pardon possible
>C errors, I've been doing Oracle PL/SQL too long):
>
># Catch function calls without valid pointer
>if (!p)
>{
>   # Display error so the programming bug doesn't go unseen
>   /* insert debug message call here */
>
>   # Prevent ourselves from crashing
>   return -1;
>}

        It's a judgement call.  That function is called from a zillion
places, and should never be called with a bad pointer.  It can't return
an error value.  That -1 implies a valid comparison to the calling
function, which will continue on that basis, and probably to something
strange.  The function doesn't know what called it, so a TRACE message
can't report that.  By letting it crash, on VMS the fatal error routine
includes a TRACEBACK, which includes the sequence of calling functions,
and other useful information.  So I was able to debug it literally in
less than a minute.  It could take hours to figure out why strange
behavior is occurring if it returned a false but seemingly valid value,
or it might be valid by chance, making it even more likely that
blatantly bad code could look OK and get out the door.

                                Fote

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 Foteos Macrides            Worcester Foundation for Biomedical Research
 address@hidden         222 Maple Avenue, Shrewsbury, MA 01545
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