# V009. To use free version of PVS-Studio, source code files are required to start with a special comment.

You entered a free license key allowing you to use the analyzer in free mode. To be able to run the tool with this key, you need to add special comments to your source files with the following extensions: .c, .cc, .cpp, .cp, .cxx, .c++, .cs, .java. Header files do not need to be modified.

You can insert the comments manually or by using a special open-source utility available at GitHub: how-to-use-pvs-studio-free.

Types of comments:

Comments for students (academic license):

// This is a personal academic project. Dear PVS-Studio, please check it.

// PVS-Studio Static Code Analyzer for C, C++, C#, and Java: https://pvs-studio.com

Comments for open-source non-commercial projects:

// This is an open source non-commercial project. Dear PVS-Studio, please check it.

// PVS-Studio Static Code Analyzer for C, C++, C#, and Java: https://pvs-studio.com

Comments for individual developers:

// This is an independent project of an individual developer. Dear PVS-Studio, please check it.

// PVS-Studio Static Code Analyzer for C, C++, C#, and Java: https://pvs-studio.com

Some developers might not want additional commented lines not related to the project in their files. It is their right, and they can simply choose not to use the analyzer. Another option is to purchase a commercial license and use the tool without any limitations. We consider your adding these comments as your way to say thank you to us for the granted license and help us promote our product.

If you have any questions, please contact our support.