To get a trial key
fill out the form below
Team License (a basic version)
Enterprise License (an 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.

What amazes me while developing the sta…

What amazes me while developing the static code analyzer

Nov 28 2011

When developing any programmer tool, be it a compiler or a static analyzer, or anything else, it is naturally that programmers use test projects the tool is constantly ran on. For example, when developing our static analyzer, we run it on 70 real projects. It allows us to make sure that everything is alright and nothing is broken. Besides, when we develop new diagnostic rules, we can see the code fragments where the new errors have been detected, after running the tests. Everything is logical and obvious. But why did I entitle the post in that way?

The point is that using the test base of projects is an established practice in our company. We wrote articles about errors in eMule, WinMerge, TortoiseSVN, etc. long ago and seem to know them through and through. But it turns out that we do not: again and again we manage to find new funny code fragments.

For example:

void CIrcMain::Disconnect(bool bIsShuttingDown)
 if (m_pIrcSocket != NULL)
  delete m_pIrcSocket;

Well, the code even may work. In some cases. Sometimes. Actually when m_pIrcSocket is not equal to NULL. However, the author is not sure that m_pIrcSocket is always not equal to NULL and has added a check to verify that. But it goes AFTER the variable is used. Therefore, the program will crash if the code is executed with m_plrcSocket present, even despite the check that it is not equal to NULL.

Here is one more similar example:

  if (!frmExist)
    frmExist = 

  if (NULL != tag && NULL != data)

The tag variable is dereferenced first and only then is checked. My question is the same: if the author is sure that tag is not equal to NULL, what for does he/she check it? And if he/she is not sure, then this check must go earlier in the code.

So, going back to the phrase I used as a title for this post. What amazes me is that though we have ALREADY found so many errors in our test projects, we are still finding new ones. It's logical on the one hand, for the analyzer is developing and consequently becomes able to find new issues. On the other hand it is amazing. We have examined all those test projects for so many times, so it seems there is nothing new to be found there. But there is.

Well, and the most obvious conclusion is: feel confident to run a static code analyzer on your project again and again because you may find new errors even in the old code, not to speak about the fresh code.

Popular related articles
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…
The way static analyzers fight against false positives, and why they do it

Date: Mar 20 2017

Author: Andrey Karpov

In my previous article I wrote that I don't like the approach of evaluating the efficiency of static analyzers with the help of synthetic tests. In that article, I give the example of a code fragment…
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…
Characteristics of PVS-Studio Analyzer by the Example of EFL Core Libraries, 10-15% of False Positives

Date: Jul 31 2017

Author: Andrey Karpov

After I wrote quite a big article about the analysis of the Tizen OS code, I received a large number of questions concerning the percentage of false positives and the density of errors (how many erro…
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…
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…
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…
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…
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…
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…

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 →