Improve Multiplatform Code With __has_include and Feature Test Macros

Two weeks ago, I showed you a sample that can detect if a function has a given overload. The example revolved around std::from_chars - low-level conversion routine for C++17. In the example, some “heavy” template patterns helped me to write the final code (most notably std::void_t and if constexpr). Maybe there are some other techniques we can use to check if a feature is available or not?

Today I’d like to have a look at __has_include and discuss the upcoming feature test macros that we’ll have in C++20.

Five Awesome C++ Papers for Cologne ISO Meeting

Today is the start day of Summer C++ISO meeting, this time in Cologne, Germany! This is the “feature-complete” meeting for C++20. It’s the last time we’ll see some new elements that are merged into the working draft.

Let’s see what’s already in C++20 and let’s have a look at some smaller, but very handy proposals that might get into the standard. This is similar to article that I did for Kona and San Diego Meetings.

How To Detect Function Overloads in C++17, std::from_chars Example

The problem: a library function offers several overloads, but depending on the implementation/compiler, some of the overloads are not available. How to check the existence of an overload? And how to provide a safe fallback?

In this article, I’ll show you a background “theory” and one case - std::from_chars that exposes full support for numbers or only integer support (in GCC, Clang).

[Quick Case] Surprising Conversions of const char* to bool

If you have two function overloads foo(): one is taking const std::string& and the other taking bool. Which one of them will be selected when you call foo("hello world"); ?

Let’s see where such a case might bite us and cause troubles?

C++17 In Detail, June Update: Foreword and Printing Tests

Last Friday my book got a fresh update! It’s been three months since the previous release, and this time I brought foreword, new book format and some small content changes.

Space Game: A std::variant-Based State Machine by Example

One of a powerful uses of std::variant is to implement State Machines. Some time ago I showed a simple example, but today we have something bigger. In today’s article by Nikolai Wuttke you’ll see how to leverage std::variant and build a space game!

Heterogeneous Lookup in Ordered Containers, C++14 Feature

If you have a map of strings, like std::map<std::string, int> m; and you want to find some element by m.find("abc"). Do you have to pay the price and construct a std::string object? Can you optimize it?

Let’s have a look at one feature enabled in C++14 that might help optimize such container access.

[Tip] How to Reference the C++ Standard or a Proposal

You’re writing a document about C++, one feature or some cool programming technique. At one point you think that you have to prove that something works and that’s why you need to quote text from the Standard. How to do it?

C++ Links #29 - recommended resources about coroutines

Welcome to new C++ Links - most important and useful articles, podcasts and videos that happen between 11th and 17th of May 2019.

In this week you will find links for two interesting resources: one about coroutines and the second about modern C++. You will also find a link describing what is the point of declaration, how to use constexpr for investigating errors and many more!

C++ Links #28 - No more erase-remove idiom!

Welcome to new C++ Links - most important and useful articles, podcasts and videos that happen between 4th and 10th of May 2019.

Today you will find a link to a video that shows how Uniform Container Erasure will simplify erasing elements from containers, link to an introduction to modules, and tutorial how to change boost::filesystem to std::filesystem.

Converting from Boost to std::filesystem

As you may know std::filesystem evolved directly from Boost filesystem library. For a long time, it was available as a Technical Specification and later merged into C++17. Developers who used Boost can ask themselves what the differences between the two libs are. Can the code be easily converted to use std::filesystem? Today’s article is written by Scott Furry who writes about the differences he found when working with the two libs.

C++ Links #27 - ADL, compiler optimisations, though C++ Quiz

Welcome to new C++ Links - most important and useful articles, podcasts and videos that happen between 27th of April 3rd of May 2019.

In this week you will find a little bit of C++ history - how namespaces were introduced in C++ and what design choices they have. You will also find a link to an extremely hard C++ quiz!

Improving Print Logging with Line Pos Info & Modern C++

No matter how proficient you are, I think, you might still use one of the primary methods of debugging: trace values using printf, TRACE, outputDebugString, etc… and then scan the output while debugging.

Adding information about the line number and the file where the log message comes from is a very efficient method that might save you a lot of time. In this post, I’ll describe one trick that is especially useful in Visual Studio but might also help in other IDE/compilers.

I’ll also show you how modern C++ and C++20 make code nicer.

Overview of std::filesystem, my talk

Last Tuesday, 16th April, I had a pleasure to talk about std::filesystem in our Cracow C++ User Group.

Here are the slides and additional comments.