Suppose I have a Python library which is distributed under the GPL license. I would like to use that library in my program, that I may eventually want to distribute under non-GPL terms.

The library itself is not pure-Python: parts of it core functionality is written in C/C++. The Python interpreter calls those C parts an "Extension", compiles as dynamically-linked library (.so or .dll), and loads during the runtime when I'm importing the library.

My concern arises from reading the GPL FAQ, where they state the following:

If a programming language interpreter has a license that is incompatible with the GPL, can I run GPL-covered programs on it?

When the interpreter just interprets a language, the answer is yes. The interpreted program, to the interpreter, is just data; the GPL doesn't restrict what tools you process the program with.

However, when the interpreter is extended to provide “bindings” to other facilities (often, but not necessarily, libraries), the interpreted program is effectively linked to the facilities it uses through these bindings. The JNI or Java Native Interface is an example of such a facility; libraries that are accessed in this way are linked dynamically with the Java programs that call them.

So if these facilities are released under a GPL-incompatible license, the situation is like linking in any other way with a GPL-incompatible library.

I find these remarks not exactly, but quite similar to the situation that I am in. So my question is: am I safe to use this GPL library or not?


I am not a lawyer, and this is not legal advice.

I'm importing the library.

Importing the library essentially means you are linking to the GPL library. Hence, your program must also be GPL.

Obviously, this site generally prefers if you release all of your software under and open source license, but we realize this is not always feasible. Depending on your use case, there may be a way to use the library without licensing your entire project under the GPL. For example, you could create a wrapper for this library and then have your main program execute the wrapper via a python os.system() or subprocess.Popen() call. In this case, you would be required to release the wrapper under the GPL, but the main program could be released under a license of your choice (assuming no other licensing restrictions by the software stack you are using). Remember not to import your wrapper or the third party library in your main executable if you go this route.


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