Dependent Names

by Rainer Grimm

A dependent name is essentially a name that depends on a template parameter. A dependent name can be a type, a non-type, or a template parameter. To express that a dependent name stands for a type or a template, you have to use the keywords typename or template...

Compiler Explorer with Cmake

by Gajendra Gulgulia

Compiler explorer has been one of the most widely used online tool for compiling C++ code, doing experiment with C++ features, sharing code snippets with friends and colleagues and also (my favorite feature) to compare and prove with the help of assembly code why a certain way of coding might be good or bad compared to another way.
Recently compiler explorer added support for compiling multiple files with CMakeLists.txt [1] . This opens up a new possibilities for developers around the world from testing complex pieces of code to testing the compilation behavior of the same.
In this issue, I would like to give a walk through on how to set up a simple layout of three files compiled with CMakelists.txt. Note that the focus is on setting up compiler explorer for multiple files and not on code efficiency. Also the article might at first glance look lengthy, but it may only be due to 19 images in the tutorial. So don’t get weighed down by the size of the article and lets start!

A Recap on User Defined Literals

by Jonathan Boccara

User defined literals were introduced in C++11, evolved in C++14 and C++17, and are a nice way to write more expressive code.

The general idea behind user defined literals is that they allow to write a value and tack on a term describing what this value represents. For example:

auto const quantity = 42_bottles_of_water;

In this expression, 42 is the value and _bottles_of_water is the user defined suffix. The expression as a whole is a user defined literal.

A common usage of user defined literals is to represent units, but they can also be used to add meaning to values in more general contexts.

Here is how to write user defined literals in C++11, C++14 and C++17...

Improving Stability with Modern C++, Part 1 — Getting Started

by Ralph Kootker, FactSet

While the C++11 standard recently had its 10th birthday, there are still developers out there using modern C++ for the first time. With that in mind, we’ve prepared a series of short introductory posts on the features of C++11 and beyond.

C++20 Coroutines — Complete* Guide

by Šimon Tóth

C++20 brought us initial support for coroutines. In this article, we will go over several examples of coroutines that build upon each other. Word of warning, though, the support in C++20 is mainly targeted at library implementors. C++23 should be bringing additional support that should cover at least the most common use cases...

C++20 Coroutine Iterators

by Martin Bond

In my first blog post about C++20 Coroutines I introduced the concepts behind a synchronous or generator style coroutine and developed a template class to support coroutines for any data type.

In this post I’ll add an iterator to the template to support the range-for loop and iterative algorithms. You may want to review that post before reading this one but the following code should act as a reminder about how to write and use a coroutine to read two floating point values into a data structure for subsequent analysis...

Smart Tricks with Parameter Packs and Fold Expressions

by Rainer Grimm

To complete my post about variadic templates and fold expressions, I present in this post smart tricks using parameter packs and fold expressions...

Concepts — case studies

by Andrzej Krzemieński

This post has been inspired by the readers’ questions about using concepts to solve real problems. We will have a look at two such problems and see if, and how, concepts can help...

Find your dream C++ job next week!

by Jens Weller

The 3rd edition of the Meeting C++ online job fair is next week on September 28th & 29th!

Each of the events lasts 3 hours in which you can hop from table to table to meet with different employers! Right now you are able to already submit your application via the CV/resume sharing form with the 3 companies sponsoring the event. The event will be hosted for the first time on Hubilo, which features a lounge as the main event part. On Tuesday the event in in the European Afternoon, which is also great for folks from Asia/Oceania to join, while the event on wednesday evening (CEST) is easier to join for folks from the Americas and Europe/Africa.

C++20 Coroutines

by Martin Bond

There seems to be a lot of confusion around the implementation of C++20 coroutines, which I think is due to the draft technical specification for C++20 stating that coroutines are a work in progress so we can’t expect full compiler and library support at this point in time.

A lot of the problems probably arise from the lack of official documentation about working with coroutines. We have been given C++ syntax support for coroutines (the co_yield and co_return) but without all of what I consider full library support. The standard library has hooks and basic functionality for supporting coroutines, but we must incorporate this into our own classes. I anticipate that there will be full library support for generator style coroutines in C++23.

The C++20 specification is obviously looking to provide support for parallel (or asynchronous) coroutines using co_await, which makes the implementation of a simpler generator style synchronous coroutines more complex. The implementation requirements for our coroutines utilises a Future and Promise mechanism similar to the std::async mechanism for asynchronous threads.

If you are a Python or C# developer expecting a simple coroutine mechanism, you’ll be disappointed because the C++20 general purpose framework is incomplete. Having said that, there are many blogs and articles on the web that include a template class that supports generator style coroutines. This blog contains a usable coroutine template and example code after discussing what a coroutine is...