Re: a missing feature in VC debugger

From:

"David Ching" <dc@remove-this.dcsoft.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sun, 09 Jul 2006 17:43:17 GMT

Message-ID:

<Vebsg.62305$Lm5.42354@newssvr12.news.prodigy.com>

"Tony Young" <jdt_young@yahoo.com> wrote in message
news:ePU96JvoGHA.4816@TK2MSFTNGP03.phx.gbl...

Hi,

From time to time, when debugging why applications crash, we found out the
cause is something similar to the following situation where p is actually
a null pointer at run time:

p->func();
or
n = p->nData;

Finding this type of bugs are sometimes time consuming because
applications may crash at a much later location. I don't know why VC6++
doesn't automatically detect such a situation and issue a warning. Does
VC2005 has such feature? This should be a handy and easy-to-implement
feature for the VC debugger. Does any other debugger support this type of
feature? Your advice is appreciated.

Both those situations should cause an 0xC00000005 exception immediately,
since you're referencing memory starting at Address 0, which is protected.
What could be happening is an exception is thrown, but your app's exception
handler masks that. To cause the debugger to break immediately, open the
Exceptions view and set the 0xC0000005 exception to "Always break" instead
of "Pass to program being debugged" (the exact phrases of these options is
probably different, but the options are there).

-- David