[CyberDildonics]

There are a lot of things being conflated here.

First is a plugin that would be shared library loaded into the same virtual memory space as a running program.

The second is GPLed header files that define function signatures and data structures.

The third scenario would be passing already defined data formats like JSON or something serialized through the file system, shared memory, or the local network. In this situation, there would be separate processes, separate memory spaces and no interface definitions would need to be included into the non GPLed program. This situation can't violated the GPL because it would imply that almost any communication with a GPLed program would violate the GPL.

[jcelerier]

> This situation can't violated the GPL because it would imply that almost any communication with a GPLed program would violate the GPL.

any intimate communication would indeed. Any communication that goes through a standard (e.g. ISO-defined or industry standard, so not something specific to your company) would not.

Quoting the FSF:

> Using shared memory to communicate with complex data structures is pretty much equivalent to dynamic linking.

You can obviously extend "communicating complex data structures" to RPC through JSON & websockets for instance as it's this "exchange of complex data structures" which is the defining matter in what constitutes a single program from the point of view of the GPL.

[CyberDildonics]

any intimate communication would indeed.

I gave specific examples and you keep using an abstract label.

> Using shared memory to communicate with complex data structures is pretty much equivalent to dynamic linking.

These are two separate things unless they are talking about shared memory meaning sharing the same memory space as another process, which is what dynamic linking does.

Communicating through complex data structures can describe files too. If you save a file from one GPLed program and open it in a non GPLed program, that is interprocess communication. If both programs are using mmap on the files instead of writes, does that change things? If files are being sent over local loop back does that change things?

Are there any examples of any of these ideas being tested? I've never heard of anyone except for you asserting that two processes communicating without including GPLed source code was somehow a GPL violation.

[jcelerier]

> I gave specific examples and you keep using an abstract label.

I am quoting the license text.

> Communicating through complex data structures can describe files too. If you save a file from one GPLed program and open it in a non GPLed program, that is interprocess communication. If both programs are using mmap on the files instead of writes, does that change things? If files are being sent over local loop back does that change things?

I don't thinkg it would at all - it would still breach the license if e.g. you are dumping raw struct contents in your files that are only meaningful for the proprietary side of things.

See https://opensource.stackexchange.com/questions/8505/gpl-appl...

[CyberDildonics]

I am quoting the license text.

The part you are quoting is still an abstract label. You can't take specific common scenarios and say 'intimate communication is banned' when 'intimate communication' is not defined well.

you are dumping raw struct contents in your files that are only meaningful for the proprietary side of things.

What does that even mean? You could work with the bmp file format internally as a frame buffer in a program because it is uncompressed. Does that mean if you write a bmp file out of gimp and open it in photoshop you are violating the GPL? If so, why has that never been brought up or asserted by any person or company ever?

The things you are saying don't seem to line up with what anyone else thinks. When has anyone else tried to claim that you can't send files from one GPL program to another non GPL program?

I think you should consider whether you are trying to claiming something is true because you want it to be true, not because it makes sense.