Stroustrup: Why the 35-year-old C++ still dominates 'real' dev -- Paul Krill, Infoworld

By Blog Staff | Aug 15, 2014 04:28 PM | Tags: None

Today in Infoworld:

Stroustrup: Why the 35-year-old C++ still dominates 'real' dev

C++ inventor details the language's latest changes and assesses the strengths and weaknesses of its competitors

by Paul Krill, Infoworld

From the interview:

Bjarne Stroustrup designed the C++ language in 1979, and the general-purpose language for systems programming has become a mainstay for developers everywhere, despite competition from Java, JavaScript, Python, Go, and Apple's newly unveiled Swift.

Now a technologist at Morgan Stanley and a professor at both Columbia University and Texas A&M University, Stroustrup spoke with InfoWorld Editor at Large Paul Krill about C++'s role today and about other happenings in software development, including Google's Go and Apple's Swift languages. ...

N4131: Another response to N4074; explicit should never be implicit -- Filip Roséen

By Blog Staff | Aug 14, 2014 03:00 PM | Tags: None

A new WG21 paper is available. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N4131

Date: 2014-08-89

Another response to N4074; explicit should never be implicit

by Filip Roséen

Excerpt:

This paper will try to prove why the proposed change of ISO C++ in N4074 shouldn't be allowed using several methods, among them are:

• Discussions of the, sometimes hidden, implications of such change, and:
• Arguments regarding how such initialization will differ from the current praxis of C++, and:
• Proof of Concepts that directly shows why such proposal is not sane.

Bjarne Stroustrup AMA -- Slashdot

By Blog Staff | Aug 14, 2014 12:17 PM | Tags: None

The live interview takes place next week. The question submission thread is open now:

Interviews: Ask Bjarne Stroustrup About Programming and C++

In addition to being the creator of C++, Bjarne Stroustrup is a Managing Director in the technology division of Morgan Stanley, a Visiting Professor in Computer Science at Columbia University, and a Distinguished Research Professor in Computer Science at Texas A&M University. Bjarne has written a number of books and was elected a member of the National Academy of Engineering. He will be doing a live Google + Q & A within the C++ community on August 20th, 2014 at 12:30pm EST, but has agreed to answer your questions first. As usual, ask as many as you'd like, but please, one per post.

Quick Q: Does make_shared avoid an extra allocation for the reference counts? -- StackOverflow

By Blog Staff | Aug 13, 2014 09:02 AM | Tags: basics

A: Yes, make_shared is your friend!

Recently on SO:

What happens when using make_shared

I'm interested if these two lines of code are the same:

shared_ptr<int> sp(new int(1)); // double allocation?
shared_ptr<int> sp(make_shared<int>(1)); // just one allocation?

If this is true could someone please explain why is it only one allocation in the second line?

CppCon 2014 Volunteers Wanted -- by Boris Kolpackov

By Blog Staff | Aug 13, 2014 08:55 AM | Tags: None

Especially if you're local to the Seattle area, this is a great way for students and others to be part of CppCon.

CppCon 2014 Volunteers Wanted

by Boris Kolpackov

Of course if you're a student you also have the option of the discounted Student registrations that let you attend the whole thing without the distraction of occasionally holding up signs and untangling A/V cords -- some Student registrations are still available. But there's also fun in being part of running things.

From the announcement:

If you would like to attend CppCon 2014, see great C++ content, and meet our speakers and attendees, but a week’s registration doesn’t fit your time or money budget, consider volunteering.

We are looking for volunteers to help run the conference. We need people to help assemble registration packets and badges, register attendees, assist speakers with Audio/Video, and in general be on hand to make things run smoothly. In exchange, we’ll see to it that you’ll spend at least half of your time in sessions. It would be great if you could join us for the whole week, but if you can only make it for one or two days, we can work with that. This is a particularly great opportunity for local students with an interest in C++. If you are interested or would like more information, please email [email protected].

CppCon Program Highlights, 12 of N: Advanced Meta Techniques

By Blog Staff | Aug 13, 2014 04:57 AM | Tags: None

The CppCon 2014 conference program has been posted for the upcoming September conference. We've received requests that the program continue to be posted in "bite-sized" posts, a few sessions at a time, to make the 100+ sessions easier to absorb, so here is another set of talks. This series of posts will conclude once the entire conference program has been posted in this way.

No C++ conference would be complete without coverage of advanced techniques that enable high performance, expressive power, or both at the same time. Here is a selection of some of the advanced topics that will be presented this year at CppCon.

In this post:

• Practical Functional Programming in C++
• Practical Type Erasure
• Pragmatic Type Erasure: Solving Classic OOP Problems with an Elegant Design Pattern
• Polymorphism with Unions
• Modern Template Metaprogramming: A Compendium

Practical Functional Programming in C++

To the untrained eye, pure functional programming may appear to be out of place in our traditionally imperative C++ world. However, the functional paradigm has become increasing prominent in production C++ codes, especially when implementing asynchronous execution.

This talk is intended as a primer for attendees who are either unfamiliar with functional programming or have doubts its practical uses in modern C++. The following topics will be covered:

* Functions as First-Class Entities (function objects, lambdas, Callable, std::function) * Higher Orders (, composition/bind) * Functions with Clear Inputs/Outputs (pure functions - side effect free) * Monads and Parallelism (future/promise, async)

Examples from different sectors of industry/academia will be presented throughout.

No prior functional programming knowledge will be needed. While this talk will cover some theory, coverage of non-C++ programming languages will be minimal. The focus of this talk will be the application of theories from FP to C++, not FP itself.

Speaker: Bryce Adelstein-Lelbach. Bryce Adelstein-Lelbach is a researcher at the Center of Computation and Technology (CCT) at Louisiana State University. He works on the HPX runtime system and his research interests include parallel and distributed programming frameworks for scientific applications. He has been working on HPX for over a year now.

Practical Type Erasure

Type erasure looks like a neat concept, but what are its real life uses? This talk will briefly show the inner workings of type erasure, and demonstrate a real working implementation of a configuration system from public domain production code. Uses and pitfalls of type erasure will also be covered.

Speaker: Cheinan Marks, Spiral Genetics. As an engineer with a chemical engineering background, Cheinan is interested in practical code and wants to take the latest advances both in science and programming and use them in real life working code along with applying engineering principles to software development. Cheinan is a senior developer at Spiral Genetics, Inc. in Seattle.

Pragmatic Type Erasure: Solving Classic OOP Problems with an Elegant Design Pattern

There are numerous, serious OOP design problems that we have all encountered in production code. These include, among others: - object lifetime/ownership - how to make classes from different class hierarchies conform to a common interface - writing classes that can present multiple interfaces - separating interface and implementation - how to write virtual functions so that subclasses override them properly - the virtual inheritance "diamond of death"

Proper use of type erasure can mitigate, or outright eliminate, these and other problems, without sacrificing performance.

This talk will cover the OOP design problems above and more, and will cover hand-rolled and library-based type erasure approaches that solve those problems. Performance metrics will be provided for the different approaches, and source code will be available after the talk.

Speaker: Zach Laine, Senior Programmer, Intific. Zach Laine has been using C++ in industry for 11 years, focusing on data visualization, numeric computing, games, generic programming, and good library design. He finds the process of writing bio blurbs to be a little uncomfortable.

Polymorphism with Unions

Using tagged unions to create families of polymorphic types that are more flexible and more easily maintained than those formed with inheritance alone. We demonstrate the design pattern and implementation techniques of sum types with examples from a compiler development project. We also examine the technique's impact on project management and engineering and on algorithm design, including the role of type switches, value type semantics, and multiple dispatch polymorphism.

Speaker: Jason Lucas, Architect, Orly Atomics. Jason Lucas is an alum of the Microsoft Visual C++ team and has been writing extensively in C++ since the early 90s. He is the architect for Orly, an open source, large-scale, distributed, transactional, and consistent graph database (all in C++) which also includes a compiler for distributed programs.

Modern Template Metaprogramming: A Compendium

Template metaprogramming has become an important part of a C++ programmer's toolkit. This talk will demonstrate state-of-the-art metaprogramming techniques, applying each to obtain representative implementations of selected standard library facilities. Along the way, we will look at void_t, a recently-proposed, extremely simple new candidate whose use has been described by one expert as "highly advanced (and elegant), and surprising even to experienced template metaprogrammers."

Speaker: Walter E. Brown . With broad experience in industry, academia, consulting, and research, Dr. Walter E. Brown has been a C++ programmer for over thirty years, joining the C++ standards effort in 2000. Among numerous other contributions, he is responsible for introducing such now-standard C++ library features as cbegin/cend and common_type as well as headers and , and has significantly impacted such core language features as alias templates, contextual conversions, and variable templates. He conceived and served as project editor for the International Standard on Special Mathematical Functions in C++. When not playing with his grandchildren, Dr. Brown is an Emeritus participant in the C++ standards process, with several more core and library proposals under consideration. He was recently appointed an associate project editor for the C++ standard itself.

CppCon 2014 Call for Lightning Talks -- Boris Kolpackov

By Blog Staff | Aug 12, 2014 03:37 PM | Tags: None

Much of the CppCon content is outside session hours, including lightning talks. Details announced today on cppcon.org:

CppCon 2014 Call for Lightning Talks

by Boris Kolpackov

From the announcement:

On Tuesday, the evening program will include Lightning Talks -- 4 talks of 15 minutes and 4 talks of 5 minutes. Expect fast paced fun with talks that are funny or intriguing from speakers at all experience levels.

If you’ve never seen a lighting talk before, check out this example (it’s just 4 and a half minutes long and funnier if you know Ruby or JavaScript) or search you tube for “lightning talk” to see a variety of examples. They cover a single topic and they start with the good stuff and make a point. Anyone can do one, but be sure to practice because 5 minutes goes by incredibly fast and 15 minutes isn’t much easier. If there’s one technique you wish everyone knew, one little known fact that should be well known, one tool that makes your life easier every day, or a collection of little things that you can fit into 5 or 15 minutes, you can propose a lighting talk, and you should.

We’ll be selecting the 8 sessions on Monday, Day 1 of the conference, from submissions we receive before and during the conference. Just email [email protected] and tell us what you want to talk about, what length you need and a little bit about yourself. Even if you don’t plan to submit, plan to attend, it’s sure to be fun!

Overload 122 is available

By Blog Staff | Aug 12, 2014 03:33 PM | Tags: intermediate

Overload 122 is now available. It contains the following C++-related articles, and more:

Overload 122

Musings on Python -- By a C++ Developer

Python and C++ are very different languages. Sergey Ignatchenko walks through things in Python that can confuse a C++ programmer

Activatable Object

Using locks will slow down threaded code. Len Holgate demonstrates how an Activatable Object can reduce the time spent blocked.

CppCon Program Highlights, 11 of N: C++11/14 Design

By Blog Staff | Aug 11, 2014 10:48 AM | Tags: None

The CppCon 2014 conference program has been posted for the upcoming September conference. We've received requests that the program continue to be posted in "bite-sized" posts, a few sessions at a time, to make the 100+ sessions easier to absorb, so here is another set of talks. This series of posts will conclude once the entire conference program has been posted in this way.

Now that we have Modern C++ in the form of C++11 and C++14, how does this change the guidance for authoring types and techniques for using them in popular patterns? In this set of talks, world-class speakers and trainers address these issues.

In this post:

• The Canonical Class
• The Implementation of Value Types
• Accept No Visitors

The Canonical Class

It was a simpler time. A period in which every college student and learn-C++-in-a-weekend duffer could write a class with the assuredness that it would behave as desired when assigned and copied. There was a check list. Complete the checklist, add some domain specific behaviour, bake in the regression oven, and you were done.

Enter C++11 with its fancy new use of the delete keyword, additional applications of explicit, rvalue references, and some perfect forwarding. How are you to write a "simple" class? Should you include a swap? What does movable mean and are there expected semantics? When is the noexcept specifier used?

During this session we will explore the boilerplate of a C++11 class. The session will touch on rvalue references, move semantics, perfect forwarding, explicit, noexcept, initializer lists, and more as it applies to producing the desired semantics for our classes and structs.

Speaker: Michael Caisse, Ciere Consulting. Michael Caisse has been crafting code in C++ for nearly 25-years. He is the owner of Ciere Consulting which provides software consulting and contracting services, C++ training, and Project Recovery for failing multidisciplinary engineering projects. :: ciere.com

The Implementation of Value Types

Predefined value types are central to C++ efficiency and robustness. More importantly, C++ provides mechanisms that enable programmers to create high-quality value types, programmers are not limited to the small predefined value types. However, implementing a high-quality type requires attention to several problems, among them portability, representation, efficient copying, efficient parameters, aliasing, constant initialization, and constant expressions. We present the issues and several approaches to implementing high-quality value types.

Speaker: Lawrence Crowl. Dr. Lawrence Crowl has expertise in programming languages, compilers, and parallel programming. He has been mixing threads with C++ for twenty-five years and is a major contributor to C++11. His goal is to achieve both high quality and high performance programs.

Accept No Visitors

Visitor Design Pattern was an attempt to overcome a limitation of object-oriented languages -- inability to retroactively introduce new polymorphic functions. While it was quite efficient in providing extensibility of functions, it was never truly retroactive, easy to teach, use or maintain, and it achieved this at the cost of hindering extensibility of classes, introduction of control inversion and requiring tons of boilerplate code to be written. Visitor Design Pattern is a workaround, not a solution to the problem and in this talk I would like to discuss a more elegant yet as efficient solution in the form of a Match statement. We will look at several use-cases for the Visitor Design Pattern, their encoding using both approaches and ultimately their advantages and disadvantages.

Speaker: Yuriy Solodkyy. Yuriy Solodkyy received his PhD from Texas A&M University, while working under the supervision of Dr. Bjarne Stroustrup on the ways to simplify the analysis of C++ programs. He is currently trying to materialize some of those ideas while working in the Visual C++ team at Microsoft. His research interests include C++, generic programming, and abstract interpretation. More information about Yuriy can be found at his university page at https://parasol.tamu.edu/~yuriys/. Website: https://parasol.tamu.edu/~yuriys/

HTTP and HTTPS in Qt

By Meeting C++ | Aug 8, 2014 03:33 AM | Tags: qt network https http basics

How to handle HTTP and HTTPs requests in Qt

HTTP and HTTPs in Qt

by Jens Weller

From the article:

Last week I started to work on an old project again: My own feed reader. I found the code 2 weeks a go on an old USB Stick, and decided to refactor it into a useful state. This involved dealing with HTTP via QNetworkAccessManager.