Re: Having friend templates in class templates
jehugaleahsa@gmail.com wrote:
I am trying to create a friend function template that can access the
members of an outer class template and an inner class template. My
class template looks something like this:
template <typename T>
struct Outer
{
// not sure how to define this function
template <typename U>
friend void doSomething(U const& value);
template <typename U>
struct Inner
{
static int num;
};
};
template <typename T>
template <typename U>
int Outer<T>::Inner<U>::num = 0;
// END example
I have been reading a template book but have not been able to resolve
my issue. Does someone know the syntax to define function doSomething?
Thanks for any help.
You are confused by the template Outer class and perceived it had
non-existant constraint on the friend function. It doesn't. The friend
function is a simple template function that has nothing to do with the
outer class except that it's granted access to all of outer class
members. Here is how you define doSomething:
template<typename U>
void doSomething(U const& value){}
Either in the same translation unit or a separate one.
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