I came across the following code: template <typename T, typename T1> auto compose(T a, T1 b) -> decltype(a + b) { return a+b; } There is one thing I cannot understand: Where could I find out what the arrow operator (->) means in the function heading? I guess purely logically, that the -> operator determines … Read more
In c++14 the decltype(auto) idiom is introduced. Typically its use is to allow auto declarations to use the decltype rules on the given expression. Searching for examples of “good” usage of the idiom I can only think of things like the following (by Scott Meyers), namely for a function’s return type deduction: template<typename ContainerType, typename … Read more
From all the material I used to learn C++, auto has always been a weird storage duration specifier that didn’t serve any purpose. But just recently, I encountered code that used it as a type name in and of itself. Out of curiosity I tried it, and it assumes the type of whatever I happen … Read more
If you read code like auto&& var = foo(); where foo is any function returning by value of type T. Then var is an lvalue of type rvalue reference to T. But what does this imply for var? Does it mean, we are allowed to steal the resources of var? Are there any reasonable situations … Read more
I can see why the auto type in C++11 improves correctness and maintainability. I’ve read that it can also improve performance (Almost Always Auto by Herb Sutter), but I miss a good explanation. How can auto improve performance? Can anyone give an example? 4 Answers 4
I’ve been using the new auto keyword available in the C++11 standard for complicated templated types which is what I believe it was designed for. But I’m also using it for things like: auto foo = std::make_shared<Foo>(); And more skeptically for: auto foo = bla(); // where bla() return a shared_ptr<Foo> I haven’t seen much … Read more
