Improved automated instance construction in C++

by Marius Elvert

In my last blog post, I wrote about how I am automatically deducing constructor parameters in my dependency injection container. The approach had a major drawback: It worked only for 2 or more parameters, since there was an ambiguity with copy- or move-constructors with exactly one parameter...

C++ Annotated May 2022: C++23 News, Optimizing C++ Apps, Pointers and Memset Tricks, and Tooling News

by Anastasia Kazakova

We are back today with all of the May news for you in our latest monthly C++ Annotated digest!

Why do arrays have to be deleted via delete[] in C++

by Mikhail Gelvih

This pointer in no case should be passed to the usual operator delete. Most likely, it will just remove the first element of the array and leave the others intact. Note that I wrote "most likely" for a reason, because no one can predict every possible outcome and the way the program will behave. It all depends on what objects were in the array and whether their destructors did something important. As a result, we get the traditional undefined behavior. This is not what you would expect when trying to delete an array.

Searching and min-max: The 114 C++ algorithms series

by Šimon Tóth

Welcome to the eighth instalment of the 114 C++ algorithms series. Today, we will discuss search algorithms that look up a specific element or count the number of matching elements and min-max algorithms...

C++23’s Deducing this: what it is, why it is, how to use it

by Sy Brand

Deducing this (P0847) is a C++23 feature which gives a new way of specifying non-static member functions. Usually when we call an object’s member function, the object is implicitly passed to the member function, despite not being present in the parameter list. P0847 allows us to make this parameter explicit, giving it a name and const/reference qualifiers...

Pass-by-value vs Pass-by-reference

by James Mitchell

Let’s dig into the age old question, should you pass-by-value or pass-by-reference in C++? (or by pointer in C)

This blog post is mostly a re-post of a reddit comment that I made on r/cpp about pass-by-value and pass-by-reference, with some minor improvements, to make it easier to reference and save.

The answer isn’t as easy as it might seem, it depends on the Application Binary Interface (ABI) and your use-cases, there isn’t a one size fits all answer, this is even more the case for anything which is built to be cross platform.

First it’s probably good to break the problem down into two parts (focusing solely on performance, ignoring readability and maintainability which should often be more important)

• The language construct costs (copying, moving, etc)
• Compiler implications (aliasing, pointer provenance, etc)
• The ABI (the stack, registers, etc)...

Ranges Improvements with C++23

by Rainer Grimm

Thanks to C++23, constructing containers will become more convenient. Additionally, the ranges library got more new views...

Porting my first Application from Qt5 to Qt6

by Jens Weller

Just this week I had the opportunity to recompile one of my Qt Applications to build it with Qt6. Here is some of the results.

The application in question manages parts of the conference, and hence is written in Qt for the UI and uses SQLite as datastorage, so Qt also used for this and as I learned for a few other things too...

Improved Iterators with Ranges

by Rainer Grimm

There are more reasons to prefer ranges library above the classical Standard Template Library. The ranges iterators support unified lookup rules and provide additional safety guarantees...

C++20 Ranges Algorithms - sorting, sets, other and C++23 updates

by Bartlomiej Filipek

This article is the third and the last one in the mini-series about ranges algorithms. We’ll look at some sorting, searching, and remaining algorithms. We’ll also have a glimpse of cool C++23 improvements in this area.

Let’s go...