Error on verge of extinction, or why I put if (x = 42) in Red List of C & C++ bugs

by Andrey Karpov

Because of this bug, developers invented the Yoda notation: a programming style where the constant is placed on the left side of the comparison operator. This style was meant to prevent a typo. If a programmer writes = instead of ==, the code won't compile.

Top 10 bugs found in C++ projects in 2022

by Vladislav Stolyarov

Here the analyzer detected that a function, marked as noexcept, calls a function that throws an exception. If an exception arises from the nothrow function's body, the nothrow function calls std::terminate, and the program crashes. It could make sense to wrap the setName function in the function-try-block and process the exceptional situation there — or one could use something else instead of generating the exception.

Challenge: can you spot an error in C++ code?

by Andrey Karpov

You'll see ten code fragments. If you manage to find an error in under 1 minute, you score one point. The 1-minute limit is made on purpose. Otherwise you'll definitely find all errors — code fragments are short. Anyway, treat this quiz as a game, and not as a real test of your programming skills

Top 10 bugs found in C++ projects in 2021

by Vladislav Stolyarov

Let's talk about... HTML! PVS-Studio provides diagnostics that don't just check code – they also look for abnormalities in string literals. The code above triggered one of these diagnostics. Such cases are quite rare. That's why, this one is so intriguing. Someone intended to create one list but added two tags that open this list instead of one. This is clearly a typo. The first tag must open the list, and the second one must close it.

PVS-Studio for JetBrains CLion: ad astra per aspera

by Evgeniy Ovsyannikov, Sergey Vasiliev

Here's an answer to the question that we are discussing - PVS-Studio and CLion collaboration will let us detect more errors at the writing code stage. CLion highlights the errors on the fly, but at the same time is limited in the analysis capabilities. PVS-Studio doesn't highlight errors immediately, but it can perform deeper analysis. Note that PVS-Studio has an incremental analysis – the mode that checks only the changed files.

Integrating PVS-Studio into uVision Keil

by Amomum

Keil provides a weird feature – creating a project batch file. I still don't know the purpose of this feature. This batch file contains all the necessary information for PVS-Studio, and it's enabled with a single check mark! Unfortunately, this check mark also breaks the incremental build. That is, any compilation becomes a complete recompilation. It affects the build time, so, unfortunately, it's not an option for us.

Example of How New Diagnostics Appear in PVS-Studio

by Andrey Karpov

As for application software development, it doesn't make sense to enable them. The CovidSim project could do without them. Otherwise, a user will simply drown in a huge number of messages that are of little use in this case. For example, when experimenting with this set of diagnostics, we received more than a million warnings for some medium-sized open projects. Roughly speaking, every third line of code might be faulty in the view of MISRA. No one will scrape through all warnings, much less fix them. The project is either developed immediately taking into account MISRA recommendations, or this coding standard is irrelevant for it.
 

Why PVS-Studio Uses Data Flow Analysis: Based on Gripping Error in Open Asset Import Library

by Andrey Karpov

It all started with checking the latest version of the Qt 6 library. There was a separate usual article on this, where I'd described 77 errors found. It turned out that at first, I decided to flip through the report, not excluding the third-party libraries' warnings. In other words, I didn't exclude the warnings related to \src\3rdparty in the settings. It so happened that I immediately ran up against a gripping error example in the Open Asset Import Library. So, I decided to write this extra little note about it.

Why PVS-Studio Doesn't Offer Automatic Fixes

by Andrey Karpov

But it only simplifies the code, not fixes it! Somebody else noticed this and opened a discussion: os_thread_windows.c - get_rel_wait() will block if abstime is in the past. As you can see, even humans make mistakes when trying to come up with a fix. Machines are just hopeless in that respect.

Checking Clang 11 with PVS-Studio

by Andrey Karpov

The programmer is using a modulo operation to get a random value of either 0 or 1. But the value 1 seems to confuse developers and make them write the classic anti-pattern in which the modulo operation is performed on 1 instead of 2. The X % 1 operation is meaningless as it always evaluates to 0.