Re: [boost] [extension] Problem with reference types

From: Robert Dailey (rcdailey_at_[hidden])
Date: 2008-07-09 20:02:43

On Wed, Jul 9, 2008 at 5:34 PM, Robert Dailey <rcdailey_at_[hidden]> wrote:

> I have the following exported factory function in a DLL I'm building on
> Windows:
>
> extern "C" void BOOST_EXTENSION_EXPORT_DECL
> export_aspects( boost::extensions::factory_map& fm )
> {
>     using namespace vfx::aspects;
>     using namespace vfx::messenger;
>
>     fm.get<Aspect, MessageReader&, unsigned int>()[0].set<Appearance>();
>     fm.get<Aspect, MessageReader&, unsigned int>()[1].set<Health>();
> }
>
> As you can see, I am specifying that each class accepts a single
> construction parameter- a reference to a MessageReader object. However, this
> isn't compiling because I don't think that it likes reference types. How can
> I specify that the constructor takes a reference? boost::ref? I would post
> the compiler warnings & errors I'm getting, however they're exceedingly
> large. Most of the warnings and errors are coming from std::map, basically
> complaining that it's trying to create a map of reference types, which can't
> possibly work. Help is appreciated.
>
> As an unrelated note, I would really like to see the template parameters
> cleaned up. There's at least 5 places I've had to redundantly specify the
> same 3 template parameters (like in the example above). I already brought
> this up in another thread, but I can't tell you how important it is. If I
> ever change the number of construction parameters my Appearance or Health
> classes take (mapped above), I will have to shift through 5 or more files
> simply to adjust all of the template parameters to make everything compile.
>

Never mind, I had a flaw in my code. The "unsigned int" and "MessageReader&"
template parameters are in the wrong spots, they need to be swapped. This
fixes everything. Sorry for the confusion!