Ranges in C++: Counted Iterables and Efficiency—Eric Niebler

New in Eric's series on ranges for C++:

Ranges in C++: Counted Iterables and Efficiency

by Eric Niebler

From the article:

I’ve been hard at work fleshing out my range library and writing a proposal to get range support into the standard. That proposal describes a foundational range concept: Iterable. An Iterable is anything we can pass to std::begin() and std::end() to get an Iterator/Sentinel pair. Sentinels, as I described here earlier this year, make it possible for the Iterable concept to efficiently describe other kinds of ranges besides iterator pairs.

The three types of ranges that we would like the Iterable concept to be able to efficiently model are:

  • Two iterators
  • An iterator and a predicate
  • An iterator and a count
The Iterator/Sentinel abstraction is what makes it possible for the algorithms to handle these three cases with uniform syntax. However, as Sean Parent pointed out here, the third option presents challenges when trying to make some algorithms optimally efficient. Back in February, when Sean offered his criticism, I promised to follow up with a blog post that justified the design. This is that post.

A video interview with Michael Wong

At C++Now this and last year I recorded a short interview with Michael Wong:

A video interview with Michael Wong

The interview as a youtube playlist

by Jens Weller

From the Article:

I've started last year a video interview in Aspen - while at C++Now - with Michael Wong. This year I had the chance to finish the interview and I am now finally able to release it. Michael is a member of the C++ Committee for many years, he leads the Canadian delegation and also speaks for IBM at the C++ committee.

Generator functions in C++—Paolo Severini

Paolo Severini expands the concept of resumable functions to support generator functions, providing the ability of lazily producing the values in a sequence only when they are needed.

Generator functions in C++

by Paolo Severini

From the article:

In the previous post we had a look at the proposal of introducing resumable functions into the C++ standard to support writing asynchronous code modeled on the C# async/await pattern.

We saw that it is already possible to experiment with the future resumable and await keywords in Visual Studio, by installing the latest November 2013 CTP. But the concept of resumable functions is not limited to asynchrony; in this post we’ll see how it can be expanded to support generator functions.

Generator functions and lazy evaluation

In several languages, like C# and Python, generator functions provide the ability of lazily producing the values in a sequence only when they are needed. ...

CppCon: My Proposed Talks (Part 2)—Herb Sutter

cppcon-108.PNGFollowing up on Herb's three talk proposals posted yesterday, the other two titles and abstracts are now posted, this time of new talks (note: again, pending review and selection by the program committee, so this is not final -- they may or may not be selected if there is stronger material).

CppCon: My Proposed Talks (Part 2)

by Herb Sutter

From the post:

GC for C++, and C++ for GC: “Right” and “Wrong” Ways to Add Garbage Collection to C++ (1 to 2 hours)

"Garbage collection is essential to modern programming!" "Garbage collection is silly, who needs it!"

As is usual with extremes, both of these statements are wrong. Garbage collection (GC) is not needed for most C++ programs; we're very happy with determinism and smart pointers, and GC is absolutely penalizing when overused, especially as a default (or, shudder, only) memory allocator. However, the truth is that GC is also important to certain high-performance and highly-concurrent data structures, because it helps solve advanced lock-free problems like the ABA problem better than workarounds like hazard pointers.

This talk presents thoughts about how GC can be added well to C++, directly complementing (not competing with) C++'s existing strengths and demonstrating why, as Stroustrup says, "C++ is the best language for garbage collection."


Addressing C++’s #1 Problem: Defining a C++ ABI (1 hour)

"Why can't I share C++ libraries even between my own internal teams without using the identical compiler and switch settings?" "Why are operating system APIs written in unsafe C, instead of C++?" "Why can’t I use std::string in a public shared library interface; it's the C++ string, isn't it?!"

These and more perennial questions are caused by the same underlying problem: For various historical reasons, C++ does not have a standard binary interface, or ABI. Partial solutions exist, from the Itanium ABI which addresses only the language and only on some platforms, to COM and CORBA which do both less and far more than is needed.

It is deeply ironic that there actually is a way to write an API in C++ so that it has a de facto stable binary ABI on every platform: extern "C".

This session describes current work driven by the presenter to develop a standard C++ ABI. This does not mean having identical binaries on all platforms. It does mean tackling all of the above problems, including directly addressing the #1 valid reason to use C instead of C++, and removing a major obstacle to sharing binary C++ libraries in a modern way.

Range Comprehensions—Eric Niebler

Do you "comprehend" ranges? From a key participant in some of the latest discussion about ranges for C++:

Range Comprehensions

by Eric Niebler

From the article:

I’ve been busy since I last wrote about ranges. I have a lot of news to share, but in this post, I’m going to narrowly focus on a recent development that has me very excited. It’s a new feature that I’m calling range comprehensions, and they promise to greatly simplify the business of creating custom ranges...

Async-Await in C++—Paolo Severini

severini-await.PNGParis, April 2014: Paolo Severini explores the Async-Await pattern and the related proposal for C++17, showing also an example by using Visual Studio 2013 November CTP.

Async-Await in C++

by Paolo Severini

From the article:

... what about native [C++] programming? Is there anything like async/await that we can use with our futures? We can find the answer in N3858, another proposal made by Gustafsson et al. for C++17.

This time the changes proposed are to the language itself and not just to the library. The idea is to introduce the equivalent of C# async methods in the form of resumable functions. They can be thought as the basis to add to C++ the support for real co-routines, and are not strictly related to the <future> library, even though they have being defined especially to improve the usability of futures and promises...

Parallel STL: Democratizing Parallelism in C++—Artur Laksberg

Today on VCblog:

Parallel STL: Democratizing Parallelism in C++

by Artur Laksberg

From the article:

Over the last few years, a group of software engineers from Intel, Microsoft and NVidia have worked together on a proposal for the ISO C++ Standard known as the "Parallel STL".

This proposal builds on the experience of these three companies building parallel libraries for their platforms -- the Threading Building Blocks (Intel), PPL and C++ AMP (Microsoft) and Thrust (NVidia). All these libraries have a common trait -- they allow developers to perform common parallel operations on generic containers. Naturally, this aligns very well with the goals of the C++ Standard Template Library.

All three companies are working on their implementations of the proposal. Today, we're pleased to announce that Microsoft has made the prototype of the proposal available as an open source project at ParallelSTL.codeplex.com.

We encourage everyone to head over to our CodePlex site and check it out. The proposal has been approved to be the foundation for the "Parallelism Technical Specification" by the ISO C++ Standards Committee ...

CppCon 2014 Registration Open: September 7-12, Bellevue, WA, USA

cppcon-173.PNGThe Standard C++ Foundation is very pleased to announce the first annual CppCon.


Registration is now open for CppCon 2014 to be held September 7–12, 2014 at the Meydenbauer Center in Bellevue, Washington, USA. The conference will start with the keynote by Bjarne Stroustrup titled "Make Simple Tasks Simple!"

CppCon is the annual, week-long face-to-face gathering for all C++ users. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in the beautiful Seattle neighborhood and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.

What you can expect at CppCon:

  • Invited talks and panels: The CppCon keynote by Bjarne Stroustrup will start off a week full of insight from some of the world’s leading experts in C++. Still have questions? Ask them at one of CppCon’s panels featuring those at the cutting edge of the language.
  • Presentations by the C++ community: What do embedded systems, game development, high frequency trading, and particle accelerators have in common? C++, of course! Expect talks from a broad range of domains focused on practical C++ techniques, libraries, and tools.
  • Lightning talks: Get informed at a fast pace during special sessions of short, less formal talks. Never presented at a conference before? This is your chance to share your thoughts on a C++-related topic in an informal setting.
  • Evening events and “unconference” time: Relax, socialize, or start an impromptu coding session.

CppCon’s goal is to encourage the best use of C++. The conference is a project of the Standard C++ Foundation, a not-for-profit organization whose purpose is to support the C++ software developer community and promote the understanding and use of modern, standard C++ on all compilers and platforms.

Looking at C++14

A few weeks ago the C++ committee did meet in Issaquah, its most important result: the final draft for C++14. See Herb Sutters trip report for details, I have written an overview based on his trip report, clangs C++14 status page and of course the papers it self.

Looking at C++14

by Jens Weller

From the Article:

As I have read through most papers of last and this year, a short overview which papers now have made it into the standard. So, what are the new features of C++14? Already before the last meeting, clang had implemented all known C++14 features of the draft published after the Chicago meeting.