Robert Ramey wrote:
While we're at it, I would also like to consider enforcing a rule that there can be at most one instance of serialization code for a specific type existing at one time.
What do you mean? If there are two DLL defining the same function but with different bodies, that's ODR violation. If they define the same function with the same body, that's no problem.
Exactly. But since the code resides in different DLLS which are not visible at compiler time, the ODR violaton cannot be detected by either the compiler or the linker. Actually I'm not sure what happens when one dynamically loads two different DLLS which contain the same function signatures. I suppose its implementation dependent.
If by implementation dependent you mean OS dependent, that is correct. In Windows code called through a dynamically loaded DLL: 1) Must be exported by the DLL 2) Is called using a DLL handle to the particular DLL ie. int (*p)(int); HMODULE h(LOadLibrary("SomeDllName"); // HMODULE is the DLL handle FARPROC fp(GetProcAddress(h,"SomeFunctionName")); // SomeFunctionName must be exported p = reinterpret_cast<p>(fp); int result(p(n...)); // where n is some integer As you say, there is no ODR violation because this does not happen at compile-time but at run-time.