[ApolloFortyNine]

The FSF thinks it counts as a derivative work and you have to use the LGPL to allow linking.

However, this has never actually been proven in court, and there's many good arguments that linking doesn't count as a derivative work.

Old post by a lawyer someone else found (version 3 wouldn't affect this) [1]

For me personally I don't really understand how, if dynamic linking was viral, using linux to run code isn't viral. Surely at some level what linux does to run your code calls GPLed code.

It doesn't really matter though, since the FSF stance is enough to scare companies from not using it, and any individual is highly unlikely to be sued.

[1] https://www.linuxjournal.com/article/6366

[JoshTriplett]

> For me personally I don't really understand how, if dynamic linking was viral, using linux to run code isn't viral. Surely at some level what linux does to run your code calls GPLed code.

The Linux kernel has an explicit exception for userspace software:

> NOTE! This copyright does not cover user programs that use kernel services by normal system calls

[jcelerier]

And the GPL also has an explicit exception for "system" software such as kernel, platform libraries etc.:

> The "System Libraries" of an executable work include anything, other than the work as a whole, that (a) is included in the normal form of packaging a Major Component, but which is not part of that Major Component, and (b) serves only to enable use of the work with that Major Component, or to implement a Standard Interface for which an implementation is available to the public in source code form. A "Major Component", in this context, means a major essential component (kernel, window system, and so on) of the specific operating system (if any) on which the executable work runs, or a compiler used to produce the work, or an object code interpreter used to run it.

> The "Corresponding Source" for a work in object code form means all the source code needed to generate, install, and (for an executable work) run the object code and to modify the work, including scripts to control those activities. However, it does not include the work's System Libraries, or general-purpose tools or generally available free programs which are used unmodified in performing those activities but which are not part of the work.