Question

Is there a way I can assert that two constant expressions are equal at compile time?

e.g. I want this to cause a compile-time error

enum { foo=263, bar=264 };
SOME_EXPRESSION(foo,bar)

but I want this to not cause an error

enum { foo=263, bar=263 };
SOME_EXPRESSION(foo,bar)

---

edit: the above was simplified. My situation is more like

some_other_file_I_dont_control.h:

class X
{
public:
   enum { foo=263 };
}

my_file.h:

enum { bar=something+somethingelse }; // bar should equal X::foo
SOME_EXPRESSION(X::foo, bar)

Answer 1

See static_assert (C++0x only); if on an older version, see Boost’s StaticAssert.