What about this.

Move the entire definition of Connection to a base object, such as ConnectionBase, except for the method(s) (I only see one) that need to include the Query object. Put ConnectionBase in a different .h file.

Make the Query dependent upon ConnectionBase, which is not dependent upon Query. It should take very little wizardry to treat a Connection object as a ConnectionBase invisibly (At worst you'll need an operator on the Connection object but I don't think you'll even need that).

Such changes would then, I would think, be invisible to the client.

All of this would be moot if gcc simply supported the 'export' keyword.

Warren Young wrote:

GCC 3.4.2. And yet again, they've managed to tighten down the C++ language the compiler accepts.

I'm stuck on a big one: the circular dependency betwen Connection and Query. The Connection class must #include query.h for various reasons; query() member function, for instance. Likewise, Query needs access to the declaration of class Connection, to be able to expand some of the template member functions that it declares. GCC won't defer expansion of the templates like it used to, until both headers are fully parsed.