May 2018

Using C++17 std::optional--Bartlomiej Filipek

A reminder.

Using C++17 std::optional

by Bartlomiej Filipek

From the article:

Let’s take a pair of two types <YourType, bool> - what can you do with such composition?

In this article, I’ll describe std:optional - a new helper type added in C++17. It’s a wrapper for your type and a flag that indicates if the value is initialized or not. Let’s see where it can be useful and how you can use it.

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.

‘Speedy Gonzales’ Serializing (Re)Actors via Allocators--"No Bugs" Hare


‘Speedy Gonzales’ Serializing (Re)Actors via Allocators

by "No Bugs" Hare

From the article:

As we briefly discussed in Part I of this mini-series [NoBugs17a], message-passing technologies such as (Re)Actors (a.k.a. Actors, Reactors, ad hoc FSMs, and event-driven programs) have numerous advantages – ranging from being debuggable (including post-factum production debugging), to providing better overall performance.

In [NoBugs17a] and [NoBugs17b], we discussed an approach to handling allocations for (Re)Actors, and then were able to achieve a safe dialect of C++ (that is, as long as we’re following a set of well-defined local rules). Now, let’s take a look at another task which can be facilitated by per-(Re)Actor allocators – specifically, at the task of serializing (Re)Actors that are later going to be de-serialized by the same executable. While one solution for this task was provided in [Ignatchenko-Ivanchykhin16], the proposed ‘ultra-fast’ serialization is rather cumbersome to maintain, and in most cases it can be beaten performance-wise by serializing at the allocator level...

Passing Booleans to an Interface in an Expressive Way--Jonathan Boccara

Readability is important.

Passing Booleans to an Interface in an Expressive Way

by Jonathan Boccara

From the article:

In order to allow a function to behave in several different way, and to allow its caller to choose amongst these behaviours, we have several tools at our disposal. Plenty, actually.

There are various sorts of polymorphisms embedded in the language such as virtual functions and templates. And we’ve also seen that a caller can specify the desired behaviour explicitly at call site. We’ve seen how to accomplish this by using tag dispatching, and also how to choose between enums and tag dispatching depending on your need.

I now want to top it off with a really simple technique, that will cost you almost nothing, but one that will make your code much more expressive. And even if it’s not rocket science I’m sharing this with you today because I’ve seen many a piece of code that could have benefited from it...

CopperSpice: Lambdas in C++

New video on the CopperSpice YouTube Channel:

Lambdas in C++

by Barbara Geller and Ansel Sermersheim

About the video:

In this video, we cover an introduction to C++ lambdas, how they differ from function pointers and functors, and why the term functor should really be avoided. We also give a brief overview of how lambdas have been extended since they were introduced in C++11.

Please take a look and remember to subscribe!

Without form and void--Barry Revzin

Did you encounter the problem?

Without form and void

by Barry Revzin

From the article:

In C++, void is a pretty strange thing. We can cast expressions to void, throw-expressions have void type, void* can point to anything, and void functions can actually return back to the caller. But we can’t have objects of type void or even write a type like void&. A function declaration like void f(void) is actually a nullary function. It’s a bit weird — but it’s not something a lot of people lose sleep over.

Until it starts wreaking havoc on your generic code — because it’s like the vector<bool> of the type system...

[[trivial_abi]] 101--Arthur O’Dwyer


[[trivial_abi]] 101

by Arthur O’Dwyer

From the article:

Finally, a blog post on [[trivial_abi]]!

This is a brand-new feature in Clang trunk, new as of about February 2018. It is a vendor extension to the C++ language — it is not standard C++, it isn’t supported by GCC trunk, and there is no active WG21 proposal to add it to the standard C++ language, as far as I know...

Submission Reminder--cppcon

Don't forget.

Submission Reminder

by cppcon

From the article:

The deadline for session submissions is only days away. Review the Call for Submissions and make your submission soon. You can run your ideas by the Submission Advice mailing list, but you must hurry for this. The advice list gets very busy as the deadline draws near...

CppCast Episode 148: C++ Simplicity with Kate Gregory

Episode 148 of CppCast the only podcast for C++ developers by C++ developers. In this episode Rob and Jason are joined by Kate Gregory to discuss her recent talk at ACCU, Pluralsight courses and the new include C++ community.

CppCast Episode 148: C++ Simplicity with Kate Gregory

by Rob Irving and Jason Turner

About the interviewee:

Kate Gregory has been using C++ since before Microsoft had a C++ compiler, and has been paid to program since 1979. She loves C++ and believes that software should make our lives easier. That includes making the lives of developers easier! She'll stay up late arguing about deterministic destruction or how C++ these days is not the C++ you remember.

Kate runs a small consulting firm in rural Ontario and provides mentoring and management consultant services, as well as writing code every week. She has spoken all over the world, written over a dozen books, and helped thousands of developers to be better at what they do. Kate is a Microsoft Regional Director, a Visual C++ MVP, an Imagine Cup judge and mentor, and an active contributor to StackOverflow and other StackExchange sites. She develops courses for Pluralsight, primarily on C++ and Visual Studio. Since 2014 she was Open Content Chair for CppCon, the largest C++ conference ever held, where she also delivered sessions.