experimental

Spaceship Operator--Simon Brand

The future?

Spaceship Operator

by Simon Brand

From the article:

You write a class. It has a bunch of member data. At some point, you realise that you need to be able to compare objects of this type. You sigh and resign yourself to writing six operator overloads for every type of comparison you need to make. Afterwards your fingers ache and your previously clean code is lost in a sea of functions which do essentially the same thing. If this sounds familiar, then C++20’s spaceship operator is for you. This post will look at how the spaceship operator allows you to describe the strength of relations, write your own overloads, have them be automatically generated, and how correct, efficient two-way comparisons are automatically rewritten to use them...

CppCon 2017: Building C++ Modules--Boris Kolpackov

Have you registered for CppCon 2018 in September? Registration is open now.

While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2017 for you to enjoy. Here is today’s feature:

Building C++ Modules

by Boris Kolpackov

(watch on YouTube) (watch on Channel 9)

Summary of the talk:

C++ Modules TS is now implemented (to various degrees) by GCC, Clang, and MSVC. The aim of this talk is to provide practical information on the mechanics of creating and consuming modules with these compilers. It is based on our experience adding modules support to the build2 toolchain and then modularizing some of its components.

We start with a brief introduction to C++ modules, why we need them, and how they relate to other physical design mechanisms, namely headers, namespaces, and libraries.

Next we explore the kind of integration modules will require from a C++ build system. Specifically, when and where a module binary interface is built? How can a build system discover which modules are needed? What are the implications for parallel and distributed builds? Can we finally get rid of the preprocessor? And what happens to header-only libraries in this brave new modularized world?

With a firm understanding of the implications C++ modules have on the build process, we can try to answer some of the module design questions: What is an appropriate module granularity? Should we have separate module interface and implementation units? Can we have a dual header/module interface for legacy support? Are module-only libraries to become all the rage?

Announcing “trivially relocatable”-- Arthur O’Dwyer

Do you want this?

Announcing “trivially relocatable”

by Arthur O’Dwyer

From the article:

Frequent users of Compiler Explorer, a.k.a. godbolt.org, may have noticed that a few days ago a new compiler appeared in its dropdown menu. “x86-64 clang (experimental P1144)” is a branch of Clang which I have patched to support the concept of “trivially relocatable types,” as described in my C++Now 2018 talk and as proposed for standardization in my upcoming paper P1144 “Object relocation in terms of move plus destroy” (coauthored with Mingxin Wang)...

CppCon 2017: A modern formatting library for C++--Victor Zverovich

Have you registered for CppCon 2018 in September? Early bird registration is open now.

While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2017 for you to enjoy. Here is today’s feature:

A modern formatting library for C++

by Victor Zverovich

(watch on YouTube) (watch on Channel 9)

Summary of the talk:

Come learn about the intricacies of C++ formatting, from stdio to iostream to the new standard proposal P0645R0: Text Formatting. The new proposal combines variadic templates with a Python-like format string syntax and is designed for performance, extensibility, and safety. It is based on the popular fmt library that has been successfully used in numerous projects in such diverse areas as gaming, mathematical optimization, autonomous vehicles, databases, logging libraries and more.

App-level Developer on std::error Exceptions Proposal for C++. Part II. The Discussion.--"No Bugs" H

Nothing is easy.

App-level Developer on std::error Exceptions Proposal for C++. Part II. The Discussion.

by "No Bugs" Hare

From the article:

For quite a long while, in certain parts of C++ community, there is a substantial resistance to existing C++ exceptions; this leads to an alternative subculture of using error codes instead of exceptions, so there are effectively two barely-compatible C++ worlds: world-using-exceptions, and world-using-error-codes...

std::iterator is deprecated: Why, What It Was, and What to Use Instead--Jonathan Boccara

You've been warned.

std::iterator is deprecated: Why, What It Was, and What to Use Instead

by Jonathan Boccara

From the article:

C++17 has deprecated a few components that had been in C++ since its beginning, and std::iterator is one of them.

If you don’t have C++17 in production, you’re like most people today. But one day or the other, your will have it, most likely. And when that day comes, you’ll be glad you anticipated the deprecation of such components, and stopped using them well in advance.

Let’s see how std::iterator was used, why it was deprecated, and what to use instead.

March 2018 ISO C++ Meeting Trip Report (SG1: Concurrency and Parallelism)--Thomas Rodgers

The future is still getting closer.

March 2018 ISO C++ Meeting Trip Report (SG1: Concurrency and Parallelism)

by Thomas Rodgers

From the article:

This year’s Winter ISO C++ Standard Committee meeting was held in March in Jacksonville, Florida. A number of larger features, for which there is substantial interest but which are also difficult to get right, were discussed:

  • Concepts, along with Concept types from the Ranges TS; see P0898 and n4685
  • Modules; see n4689
  • Coroutines; see n4723
  • Networking; see n4711
  • Executors; see p0443