One of the first things that C++ programmers learn about
auto is that bare auto never deduces a reference. In the present post, I show you two examples when it seemingly does. The first one involves proxy objects. The second one concerns structured bindings from C++17.
It is often useful to have a way of ensuring that a program is running at most once (e.g. a system daemon or Cron job). Unfortunately, most commonly used solutions are not without problems. In this post, I show a simple, reliable, Linux-only solution that utilizes Unix domain sockets and the abstract socket namespace. The post includes a sample implementation in the Rust programming language.
Celery is an asynchronous task queue based on distributed message passing. It is written in Python, but the protocol can be implemented in any language. However, there is currently no C++ client that is able to publish (send) and consume (receive) tasks. This is needed when your project is written in a combination of Python and C++, and you would like to process tasks in both of these languages. In the present post, I describe a way of interoperating between Python and C++ workers via the AMQP back-end (RabbitMQ).
C++11 introduced an alternative syntax for writing function declarations. Instead of putting the return type before the name of the function (e.g.
int func()), the new syntax allows us to write it after the parameters (e.g.
auto func() -> int). This leads to a couple of questions: Why was such an alternative syntax added? Is it meant to be a replacement for the original syntax? To help you with these questions, the present blog post tries to summarize the advantages and disadvantages of this newly added syntax.
We will implement the DBSCAN clustering algorithm in Rust. As its input, the algorithm will take a distance matrix rather than a set of points or feature vectors. This will make the implemented algorithm useful in situations when the dataset is not formed by points or when features cannot be easily extracted. The complete source code, including comments and tests, is available on GitHub.
This post introduces my Rust wrapper for ssdeep by Jesse Kornblum, which is a C library and program for computing context triggered piecewise hashes (CTPH). Also called fuzzy hashes, CTPH can match inputs that have homologies. Such inputs have sequences of identical bytes in the same order, although bytes in between these sequences may be different in both content and length. In contrast to standard hashing algorithms, CTPH can be used to identify files that are highly similar but not identical.
When talking about
T&& in C++, you may have heard about universal references and forwarding references. This may get you wonder. Why there are two names for an apparently same concept? Is there any difference between them? Which one should I use? Let’s find out.
Have you ever wondered which of the following variants you should use in range-based for loops and when?
const auto&&, or
decltype(auto)? This post tries to present rules of thumb that you can use in day-to-day coding. As you will see, only four of these variants are generally useful.
Since C++11, one can put the initialization of data members directly into structure or class definition. However, this change has consequences with regards to the construction of such structures. Indeed, by adding member initializers into a structure may render your previously working code non-compilable. In the present post, I describe this change, the related issues, and explain how to get around them.