Re: [Boost-users] [ptr_container] ptr_map and cloning issues

Robert Dailey skrev:

I have a ptr_map as follows:

typedef boost::ptr_map TextureContainer;

I only use forward declarations of Texture where needed. When I'm iterating over an instance of TextureContainer, I expect to not have to do more than use the forward declaration since technically we're only iterating pointer values and the definition of Texture is not needed for this. So when I do this:

TextureContainer myTextures; TextureContainer::const_iterator it = myTextures.find( "some key" );

The above (second line) results in an extremely complex and long compiler error, but the important part of the error says what I have pasted below. Why is this error happening? Is it trying to clone Texture objects? This shouldn't be happening.

/boost/ptr_container/clone_allocator.hpp(34) : error C2514: 'rs::Texture' : class has no constructors C:\IT\work\planb\components\rs/renderer/TextureFwd.hpp(6) : see declaration of 'rs::Texture'

C:\IT\work\planb\third_party\boost\1_37_0\boost/ptr_container/clone_allocator.hpp(55) : see reference to function template instantiation 'T *boost::new_clone<U>(const T &)' being compiled/

Hm. I can't really recreate this with vc9. What compiler are you using? First, this compiles without any problems for me: class Texture; typedef boost::ptr_mapstd::string,Texture MapType; void foo( const MapType& m ) { //MapType map; MapType::const_iterator i = m.find( "foo" ); //i = map.find( "foo" ); } Now, the uncommented does not compile because the destructor may need to delete objects of type Texture, and boost::check_delete() refuses to do that on incomplete types. -Thorsten