VST Plugin that executes a command line program with arguments

I want a plugin (VST3) that simply executes a command line (with arguments).
The use case is to run a standalone audio app (say VCV Rack) when a particular DAW session file is loaded. The command line (arguments) would specify the particular project file to use with the standalone for the particular DAW session in which it is used.
I can’t find reference to this anywhere. I’m sure it is not an original idea.
Before I code such a plugin myself, I thought I’d ask if anyone has heard of this, or knows of an existing example of such a plugin?

I haven’t ever seen such a plugin myself, but it should be relatively trivial to code one up with Juce. (ChildProcess is the class to use for launching new processes.)

Thanks for the hint.
After some time away, good project to get back into the flow with Juce!

I’ve implemented a very basic VST3 plugin (windows) that calls ChildProcess.Start()
Works as standalone and in REAPER but does not work in Ableton 10 (exe not run).
I’m issueing start() at the end of the Editor constructor and not monitoring it.
Is there a preferred place I should be monitoring the process, for example retrying it if it fails to start for some reason. It’s not a realtime task compared to audio or even gui, really.
Any comments appreciated!

It now works in (all I’ve tested) Ableton, Reaper, Standalone (windows).
The process is launched from the processor class in prepareToPlay() which starts a low frequency timer and attempts to launch if not running, periodically.
source files on github

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Hi duggle.

I’ve built your VstprogLaunch on Windows 11.
I created a new JUCE plugin via Projucer and JUCE 6.1.4, and imported your 4 source files.
I can run the plugin on Reaper 6.51.
I set the exe path and the arguments, I restart the project.
But it doesn’t seem to launch any executable.
And when I try to attach a debugger, Reaper crashes.

Any idea ?

My problem seemed to solve by itself.
Don’t really know why. :slightly_smiling_face: