does typedef instantiates a template ?

[Rechard3]

i'm now writing my first project that actually REQUIRES the use of template classes.
the soon i finished the class i wanted to define some typenames that will be commonly used, but that really got me wondering:

does the key word "typedef" by itself instantiates the template class?

template <typename TYPE>
class C
{
    TYPE var;
public:
    C()  {}
    ~C() {}
};

typedef C<int> my_class_as_int;

int main()
{
    return 0;
}

does this code by itself create an (int) instance of the template?
this question might seem silly, but i really feel more comfortable when dealing with things i fully understand.

[Cubbi]

does the key word "typedef" by itself instantiates the template class?

No, explicit instantiation uses different syntax and implicit instantiation only happens under these conditions:

class template specialization is implicitly instantiated when the specialization is referenced in a context that requires a completely-defined object type or when the completeness of the class type affects the semantics of the program

this means you can even create my_class_as_int* p; and it still won't be instantiated.

For example,

template <typename TYPE>
class C
{
   typename TYPE::member_type x;
};

typedef C<int> my_class_as_int;

int main()
{
    my_class_as_int* mp; // compiles fine
//  my_class_as_int mp;  // ERROR :error: type 'int' has no members 
                         // in instantiation of template class 'C<int>'  requested here
}

[Rechard3]

@Cubbi:
can you demonstrate this please:

TYPE::member_type

i'm unfamiliar with this syntax.

EDIT :
i was just reading an example where it used:

template <typename TYPE>
class C
{
     typename TYPE::iterator    t;
};

in this example, it was clearly intended to be used with user defined (or standard class) types that defines its own iterator type.

but i want a template that can be used with basic integral types.
does these types implicitly define member_type??

EDIT 2 :

oh sorry, i get it now.
the error at line 12 is because int doesn't define an inner class called member_type and the template you created wasn't meant for simple types after all.
anyway, thank you for the fast reply.

[Cubbi]

the template you created wasn't meant for simple types after all.

Right, it's purposefully a template that can't be instantiated with TYPE=int, and if typedef alone was instantiating it, it would have failed on line 7 already.