Argument type deduction, references and rvalues
- by uj2
Consider the situation where a function template needs to forward an argument while keeping it's lvalue-ness in case it's a non-const lvalue, but is itself agnostic to what the argument actually is, as in:
template <typename T>
void target(T&) {
cout << "non-const lvalue";
}
template <typename T>
void target(const T&) {
cout << "const lvalue or rvalue";
}
template <typename T>
void forward(T& x) {
target(x);
}
When x is an rvalue, instead of T being deduced to a constant type, it gives an error:
int x = 0;
const int y = 0;
forward(x); // T = int
forward(y); // T = const int
forward(0); // Hopefully, T = const int, but actually an error
forward<const int>(0); // Works, T = const int
It seems that for forward to handle rvalues (without calling for explicit template arguments) there needs to be an forward(const T&) overload, even though it's body would be an exact duplicate.
Is there any way to avoid this duplication?
