I’ve been very excited to see that Visual Studio 2015 supports the constexpr keyword in C++. It was introduced in the C++11 standard, and is being taken further in upcoming revisions.
There are a number of uses for the keyword, but the one which excites me the most is using it for writing functions which can be executed during compilation, potentially saving a lot of runtime overhead. In this post, I’ll show a couple of quick examples.
Read more C++ constexpr functions
If you’re a programmer, you’ll be familiar with the difference between making a copy of an object, and making a reference (or a pointer) to it. If implemented correctly, the former duplicates the data, resulting in two (or more) independent instances. The latter allows the same original data to be accessed in two (or more) different ways. These concepts are common to many languages, and are essential to passing and returning data in your program.
As of C++11, you can think of ‘move’ as being a third alternative. It’s expanded the core features of the language, adding move constructors and move-assign operators to your class design arsenal. It’s required the introduction of a new type of reference as well, known as “R-value references”, which we’ll look at later.
To quote from Scott Meyers’ excellent C++11 training materials, “move is an optimization of copy”. In practical terms it’s very similar to copying, but can offer a number of advantages, especially where copying and referencing are impossible or undesirable. In this post, I’ll try to cover the basics of moves, so you can understand what they are and how you can start using them yourself.
Read more Understanding C++11 move semantics