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C++ *

General-purpose programming language. It has imperative, object-oriented and generic programming features, while also providing facilities for low-level memory manipulation

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Just take a look at SObjectizer if you want to use Actors or CSP in your C++ project

Reading time21 min
Views3.5K


A few words about SObjectizer and its history


SObjectizer is a rather small C++ framework that simplifies the development of multithreaded applications. SObjectizer allows a developer to use approaches from Actor, Publish-Subscribe and Communicating Sequential Processes (CSP) models. It's an OpenSource project that is distributed under BSD-3-CLAUSE license.


SObjectizer has a long history. SObjectizer itself was born in 2002 as SObjectizer-4 project. But it was based on ideas from previous SCADA Objectizer that was developed between 1995 and 2000. SObjectizer-4 was open-sourced in 2006, but its evolution was stopped soon after that. A new version of SObjectizer with the name SObjectizer-5 was started in 2010 and was open-sourced in 2013. The evolution of SObjectizer-5 is still in progress and SObjectizer-5 has incorporated many new features since 2013.


SObjectizer is more or less known in the Russian segment of the Internet, but almost unknown outside of the exUSSR. It's because the SObjectizer was mainly used for local projects in exUSSR-countries and many articles, presentations, and talks about SObjectizer are in Russian.


A niche for SObjectizer and similar tools


Multithreading is used in Parallel computing as well as in Concurrent computing. But there is a big difference between Parallel and Concurrent computing. And, as a consequence, there are tools targeted Parallel computing, and there are tools for Concurrent computing, and they are different.

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Total votes 13: ↑11 and ↓2+9
Comments1

PVS-Studio for Visual Studio

Reading time10 min
Views1.1K


Many of our articles are focused on anything, but not the PVS-Studio tool itself. Whereas we do a lot to make its usage convenient for developers. Nevertheless, our efforts are often concealed behind the scenes. I decided to remedy this situation and tell you about the PVS-Studio plugin for Visual Studio. If you use Visual Studio, this article is for you.
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Total votes 18: ↑18 and ↓0+18
Comments0

The dangers of using multi-character constants

Reading time2 min
Views1.4K

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During code analysis, PVS-Studio analyzes the data flow and operates variable values. Values are taken from constants or derived from conditional expressions. We call them virtual values. Recently, we have refined them in order to work with multi-character constants and this has become the reason to create a new diagnostic rule.

Introduction


Multi-character-literals are implementation-defined, so different compilers can encode them in different ways. For example, GCC and Clang set a value, based on the order of the symbols in the literal, while MSVC moves them depending on the symbol's type (regular or escape).
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Total votes 16: ↑15 and ↓1+14
Comments0

How to speed up LZ4 decompression in ClickHouse?

Reading time23 min
Views16K
When you run queries in ClickHouse, you might notice that the profiler often shows the LZ_decompress_fast function near the top. What is going on? This question had us wondering how to choose the best compression algorithm.

ClickHouse stores data in compressed form. When running queries, ClickHouse tries to do as little as possible, in order to conserve CPU resources. In many cases, all the potentially time-consuming computations are already well optimized, plus the user wrote a well thought-out query. Then all that's left to do is to perform decompression.



So why does LZ4 decompression becomes a bottleneck? LZ4 seems like an extremely light algorithm: the data decompression rate is usually from 1 to 3 GB/s per processor core, depending on the data. This is much faster than the typical disk subsystem. Moreover, we use all available CPU cores, and decompression scales linearly across all physical cores.
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Total votes 23: ↑21 and ↓2+19
Comments0

How to quickly check out interesting warnings given by the PVS-Studio analyzer for C and C++ code?

Reading time5 min
Views1K

Once in a while, programmers who start getting acquainted with the PVS-Studio code analyzer ask me: «Is there a list of warnings that accurately indicate errors?» There is no such list because uninteresting (false) warnings in one project are very important and useful in another one. However, one can definitely start digging into the analyzer from the most exciting warnings. Let's take a closer look at this topic.
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Total votes 22: ↑22 and ↓0+22
Comments0

Visual Studio C++ Template IntelliSense Populates Based on Instantiations in Your Code

Reading time1 min
Views1.4K

Ever since we announced Template IntelliSense, you all have given us great suggestions. One very popular suggestion was to have the Template Bar auto-populate candidates based on instantiations in your code. In Visual Studio 2019 version 16.1 Preview 2, we’ve added this functionality via an “Add All Existing Instantiations” option in the Template Bar dropdown menu. The following examples are from the SuperTux codebase. 


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Total votes 8: ↑8 and ↓0+8
Comments0

Cataclysm Dark Days Ahead: Static Analysis and Roguelike Games

Reading time10 min
Views4.6K
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You must have already guessed from the title that today's article will be focusing on bugs in software source code. But not only that. If you are not only interested in C++ and in reading about bugs in other developers' code but also dig unusual video games and wonder what «roguelikes» are and how you play them, then welcome to read on!
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Total votes 25: ↑25 and ↓0+25
Comments0

Wireshark 3.x: code analysis under macOS and errors review

Reading time9 min
Views1.9K

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Wireshark Foundation released the final stable-version of the popular network traffic analyzer — Wireshark 3.0.0. The new release fixes several bugs, it is now possible to analyze the new protocols, apart from that the driver on Npcap WinPcap is replaced. Here is where quoting of the announcement ends and our note about bugs in the project starts off. The projects authors definitely haven't done their best in fixing bugs before the release.

Let's collect hotfixes right now to give a motive in doing a new release :).

Introduction


Wireshark is a well-known tool to capture and analyze network traffic. The program works with the vast majority of known protocols, has intuitive and logical graphical interface, an all-powerful system of filters. Wireshark is cross-platform, works in such OSs, as: Windows, Linux, macOS, Solaris, FreeBSD, NetBSD and many others.

To do the source code analysis, we used PVS-Studio static code analyzer. To analyze the source code, first we needed to compile the project in an OS. The choice was wide not only due to the cross platform nature of the project, but also because of that of the analyzer. I chose macOS for the analysis. You can also run the analyzer under Windows and Linux.
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Total votes 24: ↑24 and ↓0+24
Comments0

SIMD Extension to C++ OpenMP in Visual Studio

Reading time5 min
Views4.9K

In the era of ubiquitous AI applications there is an emerging demand of the compiler accelerating computation-intensive machine-learning code for existing hardware. Such code usually does mathematical computation like matrix transformation and manipulation and it is usually in the form of loops. The SIMD extension of OpenMP provides users an effortless way to speed up loops by explicitly leveraging the vector unit of modern processors. We are proud to start offering C/C++ OpenMP SIMD vectorization in Visual Studio 2019.


The OpenMP C/C++ application program interface was originally designed to improve application performance by enabling code to be effectively executed in parallel on multiple processors in the 1990s. Over the years the OpenMP standard has been expanded to support additional concepts such as task-based parallelization, SIMD vectorization, and processor offloading. Since 2005, Visual Studio has supported the OpenMP 2.0 standard which focuses on multithreaded parallelization. As the world is moving into an AI era, we see a growing opportunity to improve code quality by expanding support of the OpenMP standard in Visual Studio. We continue our journey in Visual Studio 2019 by adding support for OpenMP SIMD.


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Total votes 10: ↑9 and ↓1+8
Comments0

How the CSS markup fragment broke the C++ compiler

Reading time2 min
Views1.8K

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Static analysis methodology involves various technologies. One of them is preprocessing files right before analyzing them. Preprocessed files are created by the compiler that runs in a special working mode. Unfortunately, our long-standing experience of developing a static analyzer shows that this mode is not great for testing. In this note, I'll give the example of a fresh bug in the C++ compiler from Microsoft.
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Total votes 29: ↑28 and ↓1+27
Comments1

Top 10 bugs of C++ projects found in 2018

Reading time13 min
Views7.9K
It has been three months since 2018 had ended. For many, it has just flew by, but for us, PVS-Studio developers, it was quite an eventful year. We were working up a sweat, fearlessly competing for spreading the word about static analysis and were searching for errors in open source projects, written in C, C++, C#, and Java languages. In this article, we gathered the top 10 most interesting of them right for you!

Total votes 25: ↑24 and ↓1+23
Comments0

Following in the Footsteps of Calculators: SpeedCrunch

Reading time6 min
Views1.7K

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Here we are, continuing to explore the code of calculators! Today we are going to take a look at the project called SpeedCrunch, the second most popular free calculator.

Introduction


SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL and running on Windows, Linux, and macOS.

The source code is available on BitBucket. I was somewhat disappointed by the build documentation, which could be more detailed. It says that you need «Qt 5.2 or later» to build the project, but it actually required a few specific packages, which wasn't easy to figure out from the CMake log. By the way, it is considered a good practice nowadays to include a Dockerfile into the project to make it easier for the user to set up the development environment.
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Total votes 29: ↑28 and ↓1+27
Comments0

Checking FreeRDP with PVS-Studio

Reading time10 min
Views1.7K

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FreeRDP is an open-source implementation of the Remote Desktop Protocol (RDP), a proprietary protocol by Microsoft. The project supports multiple platforms, including Windows, Linux, macOS, and even iOS and Android. We chose it to be the first project analyzed with the static code analyzer PVS-Studio for a series of articles about the checks of RDP-clients.
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Total votes 24: ↑24 and ↓0+24
Comments1

Making C++ Exception Handling Smaller On x64

Reading time8 min
Views2.3K

Visual Studio 2019 Preview 3 introduces a new feature to reduce the binary size of C++ exception handling (try/catch and automatic destructors) on x64. Dubbed FH4 (for __CxxFrameHandler4, see below), I developed new formatting and processing for data used for C++ exception handling that is ~60% smaller than the existing implementation resulting in overall binary reduction of up to 20% for programs with heavy usage of C++ exception handling.


This article in blog.
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Total votes 7: ↑7 and ↓0+7
Comments0

Following in the Footsteps of Calculators: Qalculate

Reading time7 min
Views1.4K

Previously we did code reviews of large mathematical packages, for example, Scilab and Octave, whereby calculators remained aloof as small utilities, in which it is difficult to make errors due to their small codebase. We were wrong that we haven't paid attention to them. The case with posting the source code of the Windows calculator showed that actually everyone was interested in discussing types of errors hiding in it. Moreover, the number of errors there was more than enough to write an article about that. My colleagues and I, we decided to explore the code of a number of popular calculators, and it turned out that the code of the Windows calculator was not that bad (spoiler).
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Total votes 22: ↑19 and ↓3+16
Comments3

Another way to write cross-platform apps: Neutralinojs internals and comparison with Electron and NW.js

Reading time5 min
Views9K


I am Shalitha Suranga from Sri Lanka. I started Neutralinojs project with other two members as our research project at university.


Cross-platform application development is extremely useful among software development organizations because a large end-user audience can be targeted. Earlier there were several approaches, such as writing multiple codebases per each platform, writing a single codebase using conditionals for platform selection, or using a programming language which has a cross-platform virtual machine at run-time. There were drawbacks of each like complexity of design, limited low-level accessibility and slow learning rate. Cross-platform application development with web technologies came [1] after. Electron and NW.js are most popular frameworks which allow developers to make cross-platform applications using Javascript. Basically, these popular frameworks combine embedded chromium browser and node run-time [2], [3].


These frameworks are being used to create numerous cross-platform applications. Whereas the community pointed out several unseen drawbacks of these frameworks. Large bundled application size, high memory consumption and long development workflow are the key things which were criticized through internet forums and websites [4], [5], [6], [7], [8]. Table 1.1 shows the advantages and disadvantages of Electron/NW.js.


Table 1.1: Advantages and Disadvantages of Electron/NW,js


Advantages of Electron and NW.js Disadvantages of Electron and NW.js
Development is very easy since Javascript is used Application bundle is considered as bloatware (High disk space usage)
Access native functions via node runtimeSingle codebase for all supported platforms Linux, Windows and macOS High memory consumption and slowness
Many Node modules need to be installed
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Total votes 20: ↑17 and ↓3+14
Comments3

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