Zero-allocation continuations in C++17 — Vittorio Romeo

By Vittorio Romeo | Jul 17, 2017 03:34 AM | Tags: c++14 advanced

This series of articles show the design and implementation of future-like asynchronous computation chains that do not require any dynamic memory allocation or type erasure. 

• zero-allocation continuations - part 1

• zero-allocation continuations - part 2

• zero-allocation continuations - part 3

by Vittorio Romero

From the article:

I'd like to show an alternative design [for futures] that doesn't require any allocation whatsoever and still enables users to build up asynchronous computation chains using facilities such as `when_all` and `.then`. [...] The idea behind it is to encode the entire computation chain into a single object with a huge type.

Trip Report: My First ISO C++ Standards Meeting -- Guy Davidson

By Guy Davidson | Jul 16, 2017 05:02 PM | Tags: None

Do YOU remember your first standard meeting?

Trip Report: My first ISO C++ Standards meeting

By Guy Davidson

From the article:

This was my first standards meeting and I didn’t really know what to expect: I’ve read many trip reports but they tend to speak of the results more than the process. This post will describe more of the process.

Trip report: Summer ISO C++ standards meeting (Toronto) -- Herb Sutter

By Blog Staff | Jul 15, 2017 08:10 AM | Tags: None

The Toronto ISO C++ meeting just concluded:

Trip report: Summer ISO C++ standards meeting (Toronto)

by Herb Sutter

From the article:

A few minutes ago, the ISO C++ committee completed its summer meeting in Toronto, Ontario, Canada. We had some 130 people at the meeting, representing nine national bodies. As usual, we met for six days Monday through Saturday, including several evenings.

The following are some highlights of what we achieved this week...

A C++ review community

By Meeting C++ | Jul 13, 2017 07:05 AM | Tags: meetingcpp libraries community c++14 c++11 advanced

Two new things for the C++ community: a review community and Meeting C++ certified libraries

A C++ review community

by Jens Weller

From the article:

I've been thinking about this for a while, and for now its:

• a C++ community focused on reviewing libraries: r/cpp_review
• a by Meeting C++ provided and supported certification of libraries + a listing of these.

The real difference between struct and class--Jonathan Boccara

By Adrien Hamelin | Jul 12, 2017 12:10 PM | Tags: community basics

Yes there is one.

The real difference between struct and class

by Jonathan Boccara

From the article:

“Should I use a struct or a class?”

Such is the question many C++ programmers ask themselves, or ask around to more experienced co-workers, when designing their code.

Future Ruminations -- Sean Parent

By Felix Petriconi | Jul 12, 2017 06:12 AM | Tags: performance future efficiency

This post is a lengthy answer to a question from Alisdair Meredith via Twitter

Future Ruminations

by Sean Parent

From the article:

The question is regarding the numerous proposals for a better future class template for C++, including the proposal from Felix Petriconi, David Sankel, and myself.

It is a valid question for any endeavor. To answer it, we need to define what we mean by a future so we can place bounds on the solution. We also need to understand the problems that a future is trying to solve, so we can determine if a future is, in fact, a useful construct for solving those problems.

The proposal started with me trying to solve a fairly concrete problem; how to take a large, heavily threaded application, and make it run in a single threaded environment (specifically, compiled to asm.js with the Emscripten compiler) but also be able to scale to devices with many cores. I found the current standard and boost implementation of futures to be lacking. I open sourced my work on a better solution, and discussed this in my Better Code: Concurrency talk. Felix heard my CppCast interview on the topic, and became the primary contributor to the project.

C++17/14/11: A cheatsheet of modern C++ language and library features--Anthony Calandra

By Adrien Hamelin | Jul 11, 2017 12:05 PM | Tags: community c++17 c++14 c++11

A good knowledge base:

C++17/14/11: A cheatsheet of modern C++ language and library features.

by Anthony Calandra

From the article:

Many of these descriptions and examples come from various resources (see Acknowledgements section), summarized in my own words...

It had to be done - Abusing co_await for optionals--redditsoaddicting

By Adrien Hamelin | Jul 11, 2017 11:54 AM | Tags: experimental community

The future is not here yet that it's already full of resources!

It had to be done - Abusing co_await for optionals

by redditsoaddicting

From the article:

I finally got around to playing with coroutines in the context of non-future types. I always guessed this could be done. For optionals specifically, the idea is that you do auto x = co_await foo(); and either x is the value in the optional or the function immediately returns an empty optional...

C++17 in details: Attributes

By bfilipek | Jul 10, 2017 07:36 PM | Tags: None

Another part of the series on C++17 details.

C++17 in details: Attributes

by Bartlomiej Filipek

From the article:

Previously each compiler could specify its own syntax and list of available attributes, but in modern C++ the committee tried to standardize this: there are some extracted, common parts. Plus each compiler is not blocked to add its own extensions. Maybe at some point, we’ll move away from __attribute or __declspec or #pragma?

Quick Q: How to make my custom type to work with “range-based for loops”?

By Adrien Hamelin | Jul 10, 2017 12:14 PM | Tags: intermediate c++11

Quick A: Create member functions begin() and end() returning an iterator.

Recently on SO:

How to make my custom type to work with “range-based for loops”?

The standard has been changed since the question (and most answers) were posted in the resolution of this defect report.

The way to make a for(:) loop work on your type X is now one of two ways:

• Create member X::begin() and X::end() that return something that acts like an iterator
• Create a free function begin(X&) and end(X&) that return something that acts like an iterator, in the same namespace as your type X.

And similar for const variations. This will work both on compilers that implement the defect report changes, and compilers that do not.