If you upgrade from VC6 to VC2008, then your project will automatically converted to the new format.
As a side-effect, it will also default to the new exception handling which breaks compatibilty to VC6.

Therefor this post 😉

In VC6, by default the “/EHa” exception model ist activ.
In VC200x and later, by default, the “/EHsc” exception model is active. This means that if you did not explicit specify the “/EHa” model, you will now automatically use the “/EHsc” model, which only catches C++ exceptions!

For example, the following code will work as expected and will crash in VS2008:

#include <stdio.h>
#include <tchar.h>

int _tmain()
{
  try
  {
    printf("Now doing an AV...\n");
    char *c = NULL;
    strcpy(c, "Hello");
    printf(c);
  }
  catch(...)
  {
    printf("Catched....");
  }
}

So be aware, that if you rely on asynchonus exceptions, you need to switch the expetion model in the C/C++ project settings under “Code generation | Enabled C++ Exceptions: Yes with SEH Exceptions (/EHa)“