Detection of fatal errors

Hi,

Is there any way to perform an action before program's exit, when it
encounter some kind of fatal error?
Namely I'd like to detect a fatal error and dump buffer with logs to a
file in situations like below:

---- example 1 ----
int *a = 0;
*a = 21;

---- example 1 ----
MyClass *a;
a->someFunction();


I've tried many things:
(1)
try {

} catch( ... ) {
   dumpBuffer();
}


(2)
std::set_unexpected( dumpBuffer );
std::set_terminate( dumpBuffer );

(3)
atexit( dumpBuffer );  // this is bypassed anyhow...

None of them works.
My platform is Windows XP, program is written using Qt 4.4.0, compiler
is gcc (Mingw) 3.4.5.

Cheers,
Sebastian


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