Gabriel Dos Reis <[EMAIL PROTECTED]> writes: > Jason Merrill <[EMAIL PROTECTED]> writes: > > [...] > > | > | - I don't recall suggesting that > | > | multiple types with the same name should be able to exist. > | > then you have to consider that suggestion and come with an answer. > | > | I don't see why. The point is that visibility is orthogonal to > | linkage; a class S with external linkage is still required by the ODR > | to be unique across multiple shared objects even if some of the > | symbols that refer to it can't be referenced from outside their > | defining object. The visibility restrictions place practical limits > | on how other objects can use the type, but that doesn't mean it isn't > | the same type. > > So, -concretely- what happens to a class S (e.g. associated type info object > address, address of member functions, etc.) with external linkage, > defined in multiple translation units, with say hidden visibility?
Under the current definition, this is impossible. If you have a class S defined in one object with hidden visibility, and you try to define it in a different object, you get a different class named S, just as if you'd defined it in a different namespace or similar. Thus, the type info objects are different, the member functions have different addresses, and so on. This is achived by giving the various pieces hidden visibility.
