Subj : Re: Exception occurs only when run outside the debugger *confused*
To   : comp.programming
From : Jason Curl
Date : Wed Aug 24 2005 07:24 pm

James Dow Allen wrote:
>>My program throws an exception coming from the glibmm
>>library when I start it normally. However, when I run it
>>with the debugger (KDbg), it
>>runs just fine! (no exception thrown).
>>
>>I am using g++ 3.3.5. Does anyone have an idea how odd
>>behavior like this can happen, generally?
> 
> 
> In C, use of automatic variables before initialization
> is a common source of such anomalies.  Use of uninitialized
> malloc'ed variables, or array index out of bounds are
> other possibilities.  Use of threads or longjmps could also
> be culprit; any other possibilities, anyone?

I've found that gcc-3.3 with -O0 automatically sets uninitialised 
variables to zero, so that I usually don't find the problem, until I 
turn up the optimisations. This appears to have changed in gcc-4.0.0.

The other friend I have on Linux is 'valgrind' that checks for use of 
uninitialised variables and memory leaks. This has been very useful, 
finding the occasional bug that I didn't know existed

> 
> James
>

.