C++ c++；11:std:：forward的微妙之处：身份真的有必要吗？
我设置了一个测试用例来学习完美转发C++ c++；11:std:：forward的微妙之处：身份真的有必要吗？,c++,visual-studio-2010,visual-c++,c++11,C++,Visual Studio 2010,Visual C++,C++11,我设置了一个测试用例来学习完美转发 std::string inner(const std::string& str ) { return "const std::string&"; } std::string inner(std::string& str ) { return "std::string&"; } std::string inner(const std::string&& str ) { return "const
std::string inner(const std::string& str ) {
return "const std::string&";
}
std::string inner(std::string& str ) {
return "std::string&";
}
std::string inner(const std::string&& str ) {
return "const std::string&&";
}
std::string inner(std::string&& str ) {
return "std::string&&";
}
template <typename T> void outer(T&& t) {
std::cout << "t: " << t << std::endl;
std::cout << "perfect forward: " << inner(std::forward<T>(t)) << std::endl;
std::cout << std::endl;
}
void PerfectForwarding()
{
outer("literal");
outer(lvalue);
outer(constlvalue);
outer(rvalue());
outer(constrvalue());
}
std:：forwardMyForwardforward（typename-identity:：type&t）remove\u referenceidentityremove\u referencestd:：forwardstd::forward(t)
事实上，给出的
MyForwardforwardidentityMyForwardforwardT&typename identity:：type&identity:：typeT这种差异最重要（可能也是唯一）的影响是，要使用它们的
转发MyForwardstd:：forwardremove\u reference:：typeT&&forward（typename remove\u reference:：type&T）&&std:：identity&&&std::forward(t)