Good news! You get an almost fully working FileMaker plug-in source code. I say almost because it can run command lines except for those relating to FileMaker Server. Not sure why since I can type:
in [login to view URL] and in FileMaker Pro via the plug-in and it works. But if I type:
into the [login to view URL], it shows me information, but not through the plug-in. It gives me a "?". Huh? I can put in a timeout of say 1000 milliseconds. The result changes from "?" to a blank. A slight improvement if it means the plug-in is trying to work, but I can't understand why it does not show the same info in FileMaker Pro as in Terminal.app.
Is this because something on my computer is playing silly buggers with me? It is possible. If you like, I can send you the FileMaker database file and the current version of the plug-in and you can try it at your end. Is it just me who is having the problem?
Assuming the plug-in doesn't work, your mission impossible task today is to somehow find a way to tweak the main source code of the System plug-in (the name I have given it) in order to make it work on Windows and macOS within FileMaker Pro for managing the FileMaker Server via command line. Proof of success will be in the successful build of the plug-in that I can see working. End of project is simply to hand over the updated code for me to compile in Xcode and Visual Studio.
I will supply all the required libraries to install on your computer. I can also supply a FileMaker Pro database to test the plug-in (just type in the command in a field and click the ? button to see the information it returns), a copy of FileMaker Pro, and even FileMaker Server 18 if you badly need it. I don't care really since the plug-in is more important and software is changing all the time that old stuff is quickly not worth anything (but could be valuable to you).
But if not, you definitely need:
1. FileMaker Pro to run the plug-in command (I have already built the database file for you).
2. FileMaker Server (PC and/or Mac)
3. A compiler to build the plug-in.
4. Your brilliance in C++ programming.
If this sounds like a job you can do, feel free to send your offer.