Question

I’ve got quite a nifty get fnc which returns pointer to ‘a type’. Now I would like to reuse this fnc in fnc set to set some value to this type returned by get:

template<class Tag,class Type>
set(Type t, some_value)
{
get<Tag>(t) = value;
}

The only problem I have is that: Because get returns pointer and not reference to a pointer the return type is a rvalue which for most cases is fine but not for this. Is there a way to somehow change the returned value into lvalue?

Answer 1

Dereferencing a pointer (with the * operator) yields a reference. The type of the reference depends on the type of the pointer. const T * becomes const T &, while T * becomes T &.

So, if get returns a pointer to a non-const variable, you can write:

*get<Tag>(t) = value;

If get does not meet such requirement, and you can’t change it, you’ll have to give a set method instead.