C++20 has made it possible to default comparison operators, including the three-way comparison like this. <=> can have a deduced return type, but other operators can't: struct S { friend aut...

Clang compiles this fine, but GCC and MSVC complain that operator= cannot be defaulted: #include <type_traits> template<class T> struct S { typedef typename std::enable_if<!std::is...

cppreference shows the following definition of std::in_place_t: struct in_place_t { explicit in_place_t() = default; }; inline constexpr std::in_place_t in_place{}; Why have they added an expli...

C++11 adds the ability for telling the compiler to create a default implementation of any of the special member functions. While I can see the value of deleting a function, where's the value of exp...

I found it quite odd that the following program still compiled fine despite the default constructor being private (4.8.1 g++): class A{ private: A() = default; A(const A&) = default; }; ...

Some days ago, while reading Standard C++ news I've read the post about Defaulted functions in C++11, in that article is mentioned that the user-defined constructor is less efficient than the one g...

GCC 4.5 doesn't let me do this: class foo { public: foo() = default; private: foo(foo const&) = default; foo& operator=(foo const&) = default; }; It complains that: error: 'fo...

C++0x lets you specify certain functions as defaulted: struct A { A() = default; // default ctor A(A const&) = default; // copy ctor A(A&&) = default; // move ctor A(Other); // oth...