What breaking changes are introduced in C++11?

Question

I know that at least one of the changes in C++11 that will cause some old code to stop compiling: the introduction of explicit operator bool() in the standard l

Answer 1

How is the introduction of explicit conversion operators a breaking change? The old version will still just be as "valid" as before.

Yes, the change from operator void*() const to explicit operator bool() const will be a breaking change, but only if it is used in a way that is wrong in and out of itself. Conforming code won't be broken.

Now, another breaking change is the banning of narrowing conversions during aggregate initialization:

int a[] = { 1.0 }; // error

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Edit: Just rememberer, std::identity will be removed in C++0x (see the note). It's a convenience struct to make types dependent. Since the struct really doesn't do much, this should fix it:

template
struct identity{
  typedef T type;
};