fork(1) download
copy 
  1. #include <iostream>
  2. #include <boost/type_index.hpp>
  3.  
  4. struct x{};
  5.  
  6. int main() 
  7. {
  8.  
  9.     x&& t = x();
  10.     std::cout << "\nnaked types";
  11.     std::cout << "\n l: " << std::is_lvalue_reference<x&>::value;
  12.     std::cout << "\nlr: " << std::is_lvalue_reference<x&&>::value;
  13.     std::cout << "\n r: " << std::is_rvalue_reference<x&>::value;
  14.     std::cout << "\nrr: " << std::is_rvalue_reference<x&&>::value;
  15.     std::cout << "\nlref, decltype";   
  16.     std::cout << "\n t: " << std::is_lvalue_reference<decltype(t)>::value;
  17.     std::cout << "\n 1: " << std::is_lvalue_reference<decltype(x())>::value;
  18.     std::cout << "\n m: " << std::is_lvalue_reference<decltype(std::move(t))>::value;
  19.     std::cout << "\nrref, decltype";   
  20.     std::cout << "\n t: " << std::is_rvalue_reference<decltype(t)>::value;
  21.     std::cout << "\n 1: " << std::is_rvalue_reference<decltype(x())>::value;
  22.     std::cout << "\n m: " << std::is_rvalue_reference<decltype(std::move(t))>::value;
  23.     std::cout << "\nlref, decltype(())";
  24.     std::cout << "\n t: " << std::is_lvalue_reference<decltype((t))>::value;
  25.     std::cout << "\n 1: " << std::is_lvalue_reference<decltype((x()))>::value;
  26.     std::cout << "\n m: " << std::is_lvalue_reference<decltype((std::move(t)))>::value;
  27.     std::cout << "\nrref, decltype(())";
  28.     std::cout << "\n t: " << std::is_rvalue_reference<decltype((t))>::value;
  29.     std::cout << "\n 1: " << std::is_rvalue_reference<decltype((x()))>::value;
  30.     std::cout << "\n m: " << std::is_rvalue_reference<decltype((std::move(t)))>::value;
  31.     std::cout << "\nexpr is lvalue";
  32.     std::cout << "\n t: " << std::is_same<decltype((t)), x&>::value;
  33.     std::cout << "\n 1: " << std::is_same<decltype((x())), x&>::value;
  34.     std::cout << "\n m: " << std::is_same<decltype((std::move(t))), x&>::value;
  35.     std::cout << "\nexpr is xvalue";
  36.     std::cout << "\n t: " << std::is_same<decltype((t)), x&&>::value;
  37.     std::cout << "\n 1: " << std::is_same<decltype((x())), x&&>::value;
  38.     std::cout << "\n m: " << std::is_same<decltype((std::move(t))), x&&>::value;
  39.     std::cout << "\nexpr is neither";
  40.     std::cout << "\n t: " << std::is_same<decltype((t)), x>::value;
  41.     std::cout << "\n 1: " << std::is_same<decltype((x())), x>::value;
  42.     std::cout << "\n m: " << std::is_same<decltype((std::move(t))), x>::value;
  43. }
  44.  
Success #stdin #stdout 0s 16064KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
naked types
 l: 1
lr: 0
 r: 0
rr: 1
lref, decltype
 t: 0
 1: 0
 m: 0
rref, decltype
 t: 1
 1: 0
 m: 1
lref, decltype(())
 t: 1
 1: 0
 m: 0
rref, decltype(())
 t: 0
 1: 0
 m: 1
expr is lvalue
 t: 1
 1: 0
 m: 0
expr is xvalue
 t: 0
 1: 0
 m: 1
expr is neither
 t: 0
 1: 1
 m: 0
https://ideone.com/BLvcmc
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!