Final features for C++17

In recent weeks, the C++ Committee has held a meeting in Oulu, where the final features of C++17 have been determined and it is about to become an international standard. After the last meeting in Jacksonville, I didn’t have high hopes that C++17 would bring big surprises, but the Oulu meeting worked hard to add some to the new C++17 standard. Important and interesting feature. The Reddit page provides a good overview of C++17 features, and Herb Sutter also gave a good insight into C++17 features in a recent CppCast site (and in his trip report). In addition, Michael Wong gives us a more complete overview of C++17 features.

Let’s talk about the important things first

As I said before, the meeting in Jacksonville After the meeting, many features of C++17 have been very clear. I wrote a three-part blog series offering some advice on whether to move to C++17. We will enter a new century of C++, and relevant standards will be released together with powerful technical specifications, which will become part of the next generation of C++ standards. This means that non-C++17 features (such as Concepts or Modules) will be available as plugins in upcoming compiler releases. Visual Studio currently provides modules, but GCC is the first compiler to support concept. Clang also supports modules, and both Visual Studio and Clang will soon implement module TS-based specifications.

And, I'm thinking, the next two meetings will be mainly dealing with some of the comments, feedback, and issues raised by the various national groups (aka ISO member delegations) . The C++ standard will not add new content, but will have some more or less changes. But I still hope that all these features will pass in the final review.

The final highlights of C++17

variant<int, float> v, w;
v = 12;int i = get<int>(v);
w = get<int>(v);
w = get<0>(v); // same effect as the previous linew = v; // same effect as the previous lineget<double>(v); // ill formedget<3>(v); // ill formedtry {
  get<float>(w); // will throw.}catch (bad_variant_access&) {}

if constexpr (std::is_integer ...) 
{ //integerstuff }
else if constexpr (std::is_floating_point ...) 
{ //floatingpointstuff }
else { // NaN ;) }

auto [a , b , c] = getvalues();