Template references type deducion

Question

I have a template function:

template<typename T>
void doSomething(T& value) {
    // doSomething here
}

All is ok, but passing r-value references:

doSomething(getTempVal());

Producing no matching function for call error, because particular instantiated function template expects an l-value for 1st argument. Is there any workarounds to allow template function taking both lvalue and rvalue references without adding new template?

Answer 1

Yes, just use && instead of &.

It may seem odd, because you might think that this would disallow calling it with lvalues, but actually, if T is itself an lvalue reference type, then T && is just T: it doesn't become an rvalue reference type.

In other words,

template <typename T>
void f(T &&);

int main() {
  int k = 1;
  f(k); // okay: calls f<int&>
  f(2); // okay: calls f<int>
}

Note that T can be deduced as a reference type, and the function body will need to be made to handle that.