The following code example is taken from the book
C++ Move Semantics - The Complete Guide
by Nicolai M. Josuttis,
Leanpub, 2020
The code is licensed under a
Creative Commons Attribution 4.0 International License.
// raw code
#include <iostream>
#include <string>
#include <vector>
template<typename T>
void insert(T& coll, typename T::value_type&& arg)
{
coll.push_back(arg);
}
int main()
{
std::vector<std::string> coll;
//...
insert(coll, std::string{"prvalue"}); // OK
//...
std::string str{"lvalue"};
insert(coll, str); // ERROR: T::value_type&& is not a universal reference
insert(coll, std::move(str)); // OK
//...
}