Jakub, The declaration of A a; in struct B because it requires an object size. Using a pointer to an incomplete type is allowed. You could create a new A in the B constructor and assign it to a pointer. The other errors center around this. The question about using B b has nothing to do with the error above. Corey On 10/26/05, Jakub Pawlewicz <jakub.pawlewicz@xxxxxxxxx> wrote: > > Your problem is not with templates. > > > > Here's your problem in a nutshell... > > > > struct A > > { > > int x; > > > > struct B > > { > > A a; > > }; > > }; > > > > > > You cannot use A within B, because at that point A is incomplete. > > > > You can pull B out of A. If you want B to be in the A namespace, change > > 'struct A' to 'namespace A', and make 'struct A_impl', fully declared, and > > then use that within 'struct B'. > > But what about function f(), the member of struct A? I want to declare > variable with type B in the body of the function: > > struct A { > ... > void f() > { > B b; > ... > } > }; > > I am aware that kind of code may be ill formed, but when using > templates, there should be something like deferred instantiation. > Struct B is a template and also function A::f() is a template. Struct > B is needed only when function A::f() is used. Struct B should be able > to construct member of type A and Struct B do not use function A::f(). > I want all functions be inline. Any solutions? >