Handling Exception in MFC - mfc

Question

I got this exception in my program:
Unhandled exception at 0x0051cce0 in
JSONDataParsing.exe: 0xC0000005:
Access violation reading location
0x00000004
.
I tried catching the Exception, but of no use. I know where the problem occurs. But wanted to know how I can trap the exception. I used try, catch block around the code where exception occurs.
Is this an exception which can not be caught?
The catch statements are:
catch (bad_alloc&)
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"bad_alloc \n");
OutputDebugString(msgbuf);
}
catch (bad_cast&)
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"bad_cast \n");
OutputDebugString(msgbuf);
}
catch (bad_exception&)
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"babad_exceptiond_alloc \n");
OutputDebugString(msgbuf);
}
catch (bad_typeid&)
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"bad_alloc \n");
OutputDebugString(msgbuf);
}
catch( CMemoryException* e )
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"CMemoryException \n");
OutputDebugString(msgbuf);
// Handle the out-of-memory exception here.
}
catch( CFileException* e )
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"CFileException \n");
OutputDebugString(msgbuf);
// Handle the file exceptions here.
}
catch( CException* e )
{
TCHAR msgbuf[MAX_PATH];
swprintf(msgbuf, L"CException \n");
OutputDebugString(msgbuf);
// Handle the exception here.
// "e" contains information about the exception.
e->Delete();
}

Answer 1

You can only catch such exception with a special try-catch handler:
try
{
// code that triggers such an exception. for example:
int * a = NULL;
*a = 0;
}
catch (...)
{
// now that exception is handled here
}
But generally, it is bad practice to do this. Instead you should not get such an exception but check your parameters and variables.
See here for more details:
http://members.cox.net/doug_web/eh.htm

Answer 2

This type of low level exception can be caught using __try -except statement, but you should fix the cause of it rather than reporting it. In VS, while debugging hit CTRL+ALT+E and check all exceptions there, then continue to run your app until the exception occurs. The prompt will stop on the offending line.
See
http://msdn.microsoft.com/en-us/library/s58ftw19.aspx
for details.