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.

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).

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? Intro Here’s the example once again void foo(const std::string& in) { std::cout << in << '\n'; } void foo(bool in) { std::cout << "bool: " << in << '\n';} foo("Hello World"); What’s the output?

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! This article is a guest post from Nikolai Wuttke

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.

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? Intro Referencing the C++ Standard, or maybe a proposal might be quite confusing.

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?

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.

How would you implement a function that searches for files with a given extension? For example, finding all text files? or *.cpp files? To code that solution you need a way to iterate through directories. Is that possible in C++ out of the box using the standard library? Let’s see some techniques and new elements that C++17 added.

The C ++ 17 standard consists of almost two thousands pages. Two thousand pages describing every single aspect of the language. Some pages relates to all kinds of details, exceptions, and things that you do not care about every day. We will try to look at a few such cases, which we hope never see in the production code.

In the first part of the series we looked at lambdas from the perspective of C++03, C++11 and C++14. In that article, I described the motivation behind this powerful C++ feature, basic usage, syntax and improvements in each of the language standards. I also mentioned several corner cases. Now it’s time to move into C++17 and look a bit into the future (very near future!

I released “C++17 In Detail” in August 2018, and I set the status to 90%. I didn’t expect that writing of that remaining 10% would take me so long :) Now it’s high time to set the counter to 100%. That’s why I’m pleased to announce that my book “C++17 In Detail” is now done!