I use closed-source scientific software for my work. I also use GPL licensed tools and libraries. It would save me a lot of time to be able to call a GPL library directly from the closed-source software. The closed-source program can be extended with "plugins" that are written in C, run as a separate process, but need to link against a closed-source IPC library.
Can I write a plugin to interface the closed-source software with the GPL library, for my private use?
Can I distribute the plugin as a compiled executable?
Can I distribute the source code of the plugin so others can compile it on their own computer?
I intend to release the plugin code under the most permissive open source license possible while still complying with the GPL.
Let me clarify why the answers to the linked duplicate don't answer my question:
That question refers to a GPL host application with closed-source plugins. My question is about a closed-source host with a plugin that uses GPL libraries. It's not clear to me if that makes a difference.
My understanding is that the way the plugin attaches to the host application is very relevant to the GPL's restrictions. If the plugin is a separate executable that the host launches and pipes textual input to, the restrictions don't apply. The "attachment" method I described above is somewhat atypical: the plugin is a separate process and communicates with the host through a proprietary interprocess communication method. To achieve this, the plugin executable needs to statically or dynamically link to a closed-source IPC library. Possibly at this point it won't even matter anymore that this executable is a plugin and distributing it is clearly forbidden by the GPL?