Convert C++/MFC from visual studio.net 2002 to visual studio 2010

Question

We will convert a number of programs written in C++ and MFC in Visual Studio.NET 2002 to Visual Studio 2010. What problems can we expect to encounter? What changes are there in the libraries that are worth knowing?

Answer 1

dynamic_cast will behave differently at runtime

class A
{
}

class B : public A
{
}

class C : public A
{
}

//...

C* c = new C();
//This used to work, i.e. didn't return NULL, with 2002
B* b = dynamic_cast<B*>(c); //... won't work any more --> returns NULL.

Answer 2

MFC has had a number of breaking changes over those releases. All the changes are documented on MSDN, and usually they're pretty straightforward - function signature changes and the like (which can often be fixed simply by inspecting the compiler error message and working out what it wants instead).

Answer 3

I've been through this moving a project to VS 2008 and the two big ones were the "secure CRT" functions and the for loop scope change. (I can't remember precisely when that happened, but it might affect you.) Basically the compiler is your friend ... build the whole thing and it will find the problems, which you can then fix. You can suppress the secure CRT warnings but you might as well get them taken care of.

I'm not aware of any "I'm happy to compile but I won't do quite what I used to do at runtime, thus ruining your world" breaking changes in MFC or C++ over the last decade. So once you make the compiler happy you should be confident your app still works.