GPLv2 Compliance for Dynamic Linking

Oct 13, 2025 by wbrum.org 27 views

Introduction

As a developer, you may have encountered situations where you need to use a third-party library or executable in your closed-source commercial application. One such scenario is when you want to utilize an executable published under the GNU General Public License version 2 (GPLv2). In this article, we will explore the possibilities and limitations of using an unmodified GPLv2 binary in a closed-source app.

Understanding GPLv2

Before we dive into the details, let's briefly understand the GPLv2 license. The GPLv2 is a widely used open-source license that allows users to freely use, modify, and distribute software. However, it also imposes certain conditions on the use of the software. Specifically, the GPLv2 requires that any modifications or enhancements made to the software must be disclosed and made available under the same license.

Using GPLv2 Binary in Closed-Source App

Now, let's consider the scenario where you want to use an executable published under GPLv2 in your closed-source commercial application, MyApp. In this case, you would need to ensure that you comply with the terms of the GPLv2 license.

Preparation of Inputs

To use the GPLv2 binary, ExtApp, in MyApp, you would need to prepare the inputs for ExtApp. This could involve collecting user data, processing it, and then passing it to ExtApp as input. You would also need to ensure that the inputs are in a format that ExtApp can understand.

Running ExtApp

Once you have prepared the inputs, you can run ExtApp using the inputs. This could involve creating a process or thread in MyApp that runs ExtApp and passes the inputs to it.

Retrieving Results

After running ExtApp, you would need to retrieve the results from ExtApp. This could involve reading the output from ExtApp and processing it in MyApp.

GPLv2 Compliance

Now, let's consider the GPLv2 compliance aspects of using ExtApp in MyApp. Since ExtApp is published under GPLv2, you would need to ensure that you comply with the terms of the license.

Linking vs. Incorporating

One key aspect of GPLv2 compliance is the distinction between linking and incorporating. Linking refers to the process of combining two or more programs to create a new program. Incorporating, on the other hand, refers to the process of including the source code of one program into another program.

Dynamic Linking

In the case of using ExtApp in MyApp, you would be dynamically linking to ExtApp. This means that MyApp would be using the ExtApp executable as a library, without incorporating its source code into MyApp.

GPLv2 Compliance for Dynamic Linking

In the case of dynamic linking, the GPLv2 license requires that you provide the source code of ExtApp to anyone who requests it. However, you are not required to disclose the source code of MyApp.

Static Linking

If you were to statically link to ExtApp, you would be incorporating the source code of ExtApp into MyApp. In this case, you would be required to disclose the source code of both MyApp and ExtApp.

GPLv2 Compliance for Static Linking

In the case of static linking, the GPLv2 license requires that you provide the source code of both MyApp and ExtApp to anyone who requests it.

Conclusion

In conclusion, using an unmodified GPLv2 binary in a closed-source app is possible, but it requires careful consideration of the GPLv2 compliance aspects. By understanding the distinction between linking and incorporating, and by ensuring that you comply with the terms of the GPLv2 license, you can use GPLv2 binaries in your closed-source commercial applications.

Best Practices

Here are some best practices to keep in mind when using GPLv2 binaries in your closed-source commercial applications:

Understand the GPLv2 license: Before using a GPLv2 binary, make sure you understand the terms of the license.
Ensure GPLv2 compliance: Ensure that you comply with the terms of the GPLv2 license, including providing source code when required.
Use dynamic linking: Use dynamic linking to avoid incorporating the source code of the GPLv2 binary into your closed-source application.
Disclose source code: Disclose the source code of the GPLv2 binary to anyone who requests it.

Common Misconceptions

Here are some common misconceptions about using GPLv2 binaries in closed-source commercial applications:

GPLv2 is incompatible with closed-source applications: This is not true. GPLv2 is compatible with closed-source applications, but it requires careful consideration of the GPLv2 compliance aspects.
You must disclose the source code of your closed-source application: This is not true. You only need to disclose the source code of the GPLv2 binary, not your closed-source application.

Real-World Examples

Here are some real-world examples of using GPLv2 binaries in closed-source commercial applications:

Linux: Linux is a popular open-source operating system that uses GPLv2-licensed code. However, Linux is also used in closed-source commercial applications, such as Android.
MySQL: MySQL is a popular open-source database management system that uses GPLv2-licensed code. However, MySQL is also used in closed-source commercial applications, such as Facebook.

Conclusion

Introduction

In our previous article, we explored the possibilities and limitations of using an unmodified GPLv2 binary in a closed-source app. In this article, we will answer some frequently asked questions (FAQs) about using GPLv2 binaries in closed-source commercial applications.

Q: What is GPLv2, and how does it affect my closed-source app?

A: GPLv2 is a widely used open-source license that allows users to freely use, modify, and distribute software. However, it also imposes certain conditions on the use of the software. Specifically, the GPLv2 requires that any modifications or enhancements made to the software must be disclosed and made available under the same license. If you use a GPLv2 binary in your closed-source app, you must comply with the terms of the GPLv2 license.

Q: Do I need to disclose the source code of my closed-source app if I use a GPLv2 binary?

A: No, you do not need to disclose the source code of your closed-source app if you use a GPLv2 binary. However, you must disclose the source code of the GPLv2 binary to anyone who requests it.

Q: What is the difference between linking and incorporating?

A: Linking refers to the process of combining two or more programs to create a new program. Incorporating, on the other hand, refers to the process of including the source code of one program into another program. In the case of using a GPLv2 binary in a closed-source app, you would be dynamically linking to the GPLv2 binary, not incorporating its source code into your app.

Q: Do I need to provide the source code of the GPLv2 binary to my customers?

A: Yes, if you use a GPLv2 binary in your closed-source app, you must provide the source code of the GPLv2 binary to anyone who requests it. This includes your customers.

Q: Can I use a GPLv2 binary in a closed-source app if I'm not planning to distribute it?

A: Yes, you can use a GPLv2 binary in a closed-source app even if you're not planning to distribute it. However, you must still comply with the terms of the GPLv2 license.

Q: What are the consequences of not complying with the GPLv2 license?

A: If you fail to comply with the terms of the GPLv2 license, you may be liable for copyright infringement. This could result in legal action against you and your company.

Q: Can I use a GPLv2 binary in a closed-source app if I'm planning to distribute it?

A: Yes, you can use a GPLv2 binary in a closed-source app if you're planning to distribute it. However, you must comply with the terms of the GPLv2 license and provide the source code of the GPLv2 binary to anyone who requests it.

Q: How do I ensure that I'm complying with the GPLv2 license?

A: To ensure that you're complying with the GPLv2 license, you should:

Understand the terms of the GPLv2 license
Ensure that you're using the GPLv2 binary in a way that complies with the license
Provide the source code of the GPLv2 binary to anyone who requests it
Keep records of your compliance with the GPLv2 license

Q: Can I use a GPLv2 binary in a closed-source app if I'm using a different open-source license?

A: It depends on the terms of the other open-source license. If the other license is compatible with the GPLv2 license, you may be able to use the GPLv2 binary in your closed-source app. However, you should consult with a lawyer to ensure that you're complying with the terms of both licenses.

Conclusion

Best Practices

Here are some best practices to keep in mind when using GPLv2 binaries in your closed-source commercial applications:

Understand the GPLv2 license: Before using a GPLv2 binary, make sure you understand the terms of the license.
Ensure GPLv2 compliance: Ensure that you comply with the terms of the GPLv2 license, including providing source code when required.
Use dynamic linking: Use dynamic linking to avoid incorporating the source code of the GPLv2 binary into your closed-source application.
Disclose source code: Disclose the source code of the GPLv2 binary to anyone who requests it.

Common Misconceptions

Here are some common misconceptions about using GPLv2 binaries in closed-source commercial applications:

GPLv2 is incompatible with closed-source applications: This is not true. GPLv2 is compatible with closed-source applications, but it requires careful consideration of the GPLv2 compliance aspects.
You must disclose the source code of your closed-source application: This is not true. You only need to disclose the source code of the GPLv2 binary, not your closed-source application.

Real-World Examples

Here are some real-world examples of using GPLv2 binaries in closed-source commercial applications:

Linux: Linux is a popular open-source operating system that uses GPLv2-licensed code. However, Linux is also used in closed-source commercial applications, such as Android.
MySQL: MySQL is a popular open-source database management system that uses GPLv2-licensed code. However, MySQL is also used in closed-source commercial applications, such as Facebook.