To get a trial key
fill out the form below
Team License (a basic version)
Enterprise License (extended version)
* By clicking this button you agree to our Privacy Policy statement

Request our prices
New License
License Renewal
--Select currency--
* By clicking this button you agree to our Privacy Policy statement

Free PVS-Studio license for Microsoft MVP specialists
* By clicking this button you agree to our Privacy Policy statement

To get the licence for your open-source project, please fill out this form
* By clicking this button you agree to our Privacy Policy statement

I am interested to try it on the platforms:
* By clicking this button you agree to our Privacy Policy statement

Message submitted.

Your message has been sent. We will email you at

If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

On the good of automated filtering of i…

On the good of automated filtering of identical messages

Dec 14 2011

From the very beginning duplicates of messages in our analyzer PVS-Studio have been eliminated. For example, if a diagnostic message is generated for a code in an .h-file included into several .cpp-files, our tool will generate it only once. Some other analyzers don't do that and when they check .cpp-files, they show you messages every time on the same strings in .h-files. So it turns out that our analyzer generates fewer messages compared to such tools. But we had no chance to estimate how useful it is before. Now we've got such an occasion, and the results are really impressive.

To clarify the point let me first cite a code sample. Assume we have the Foo class defined in the Foo.h file:

class Foo {
  int iChilds[2];
  bool hasChilds() const { return(iChilds > 0 || iChilds > 0); }

There are two files Usage.cpp and Play.cpp, both containing the following string:

#include "Foo.h"

When checking these files, a message will be generated: "V501. There are identical sub-expressions to the left and to the right of the 'foo' operator". The message will be generated twice (because two compilation units have been checked), but the user will see it only once, since the repeated message will be automatically filtered.

If there were no filtration, you would see 2 V501 messages: one for the Usage.cpp file and another for the Play.cpp file.

We have recently checked the source code of Mozilla Firefox. Although Firefox's code is built with Visual C++, it still doesn't contain .sln-files and is compiled through makefile. It is this makefile we have built a call of the console version of PVS-Studio into for each file (as described in the documentation). The messages in this mode are written all in a row into one large "raw" report file that can be later opened with PVS-Studio from Visual Studio. Then this "raw" report can be saved as .plog (PVS-Studio's xml-report). During conversion repeated messages are automatically filtered.

So, there were about 2 000 000 messages (with numerous duplicates) in the "raw" report. In the converted report, there were only 80 000 messages, i.e. 25 times fewer. It is this number that enables us to estimate the amount of message duplicates which are automatically filtered.

This example also confirms the idea that a static analyzer is a complex system, and it's not enough just to print error messages into stdout.

Popular related articles
PVS-Studio for Java

Date: Jan 17 2019

Author: Andrey Karpov

In the seventh version of the PVS-Studio static analyzer, we added support of the Java language. It's time for a brief story of how we've started making support of the Java language, how far we've co…
The Evil within the Comparison Functions

Date: May 19 2017

Author: Andrey Karpov

Perhaps, readers remember my article titled "Last line effect". It describes a pattern I've once noticed: in most cases programmers make an error in the last line of similar text blocks. Now I want t…
The Ultimate Question of Programming, Refactoring, and Everything

Date: Apr 14 2016

Author: Andrey Karpov

Yes, you've guessed correctly - the answer is "42". In this article you will find 42 recommendations about coding in C++ that can help a programmer avoid a lot of errors, save time and effort. The au…
Free PVS-Studio for those who develops open source projects

Date: Dec 22 2018

Author: Andrey Karpov

On the New 2019 year's eve, a PVS-Studio team decided to make a nice gift for all contributors of open-source projects hosted on GitHub, GitLab or Bitbucket. They are given free usage of PVS-Studio s…
How PVS-Studio Proved to Be More Attentive Than Three and a Half Programmers

Date: Oct 22 2018

Author: Andrey Karpov

Just like other static analyzers, PVS-Studio often produces false positives. What you are about to read is a short story where I'll tell you how PVS-Studio proved, just one more time, to be more atte…
Technologies used in the PVS-Studio code analyzer for finding bugs and potential vulnerabilities

Date: Nov 21 2018

Author: Andrey Karpov

A brief description of technologies used in the PVS-Studio tool, which let us effectively detect a large number of error patterns and potential vulnerabilities. The article describes the implementati…
PVS-Studio ROI

Date: Jan 30 2019

Author: Andrey Karpov

Occasionally, we're asked a question, what monetary value the company will receive from using PVS-Studio. We decided to draw up a response in the form of an article and provide tables, which will sho…
Appreciate Static Code Analysis!

Date: Oct 16 2017

Author: Andrey Karpov

I am really astonished by the capabilities of static code analysis even though I am one of the developers of PVS-Studio analyzer myself. The tool surprised me the other day as it turned out to be sma…
The Last Line Effect

Date: May 31 2014

Author: Andrey Karpov

I have studied many errors caused by the use of the Copy-Paste method, and can assure you that programmers most often tend to make mistakes in the last fragment of a homogeneous code block. I have ne…
Static analysis as part of the development process in Unreal Engine

Date: Jun 27 2017

Author: Andrey Karpov

Unreal Engine continues to develop as new code is added and previously written code is changed. What is the inevitable consequence of ongoing development in a project? The emergence of new bugs in th…

Comments (0)

Next comments
This website uses cookies and other technology to provide you a more personalized experience. By continuing the view of our web-pages you accept the terms of using these files. If you don't want your personal data to be processed, please, leave this site.
Learn More →