fork download 
  1. #include <iostream>
  2. #include <utility>
  3.  
  4.     struct blah {
  5.       decltype(auto) foo() & { return do_foo(*this); }
  6.       decltype(auto) foo() && { return do_foo(std::move(*this)); }
  7.       decltype(auto) foo() const& { return do_foo(*this); }
  8.       decltype(auto) foo() const&& { return do_foo(std::move(*this)); }
  9.       decltype(auto) foo() const volatile& { return do_foo(*this); }
  10.       decltype(auto) foo() const volatile&& { return do_foo(std::move(*this)); }
  11.       decltype(auto) foo() volatile& { return do_foo(*this); }
  12.       decltype(auto) foo() volatile&& { return do_foo(std::move(*this)); }
  13.  
  14.       blah( const volatile blah&& b ) {}
  15.       blah( const volatile blah& b ) {}
  16.       blah( const blah& b ) = default;
  17.       blah( blah&& b ) = default;
  18.       blah() = default;
  19.  
  20.       template<class Self>
  21.       friend blah do_foo(Self&& self) {
  22.         std::cout << "Is reference:" << std::is_reference<Self>::value << "\n";
  23.         std::cout << "Is const:" << std::is_const<std::remove_reference_t<Self>>::value << "\n";
  24.         std::cout << "Is volatile:" << std::is_volatile<std::remove_reference_t<Self>>::value << "\n";
  25.         return decltype(self)(self);
  26.       }
  27.     };
  28.  
  29. int main() {
  30. 	blah{}.foo();
  31. 	blah tmp;
  32. 	tmp.foo();
  33. 	const blah tmp2;
  34. 	tmp2.foo();
  35. }
  36.  
Success #stdin #stdout 0s 15240KB
comments (?)
stdin 
Standard input is empty
stdout 
Is reference:0
Is const:0
Is volatile:0
Is reference:1
Is const:0
Is volatile:0
Is reference:1
Is const:1
Is volatile:0
https://ideone.com/v24Ev9
language:
C++14 (gcc 8.3)
created:
6 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!