Warning when verifying sketch with VS code I use Visual Studio Code to develop for arduino which uses Arduino Studio installed files and needs the installation to work. This works very well.  

Annoying is that when verifying a sketch it takes longer than in the Arduino IDE. I suspect the following warning to cause it:


  [Warning] Output path is not specified. Unable to reuse previously
  compiled files. Verify could be slow. See README.


I would like to get rid of the warning and I searched through all README files in the arduino installation folder and I also searched google but haven't found out what its supposed to mean and how to fix it. No readme file mentions that or I overlooked it.  

Is there a documentation on how to fix this anywhere?
Thanks to @Majenko I looked some place new:

documented in the arduino plugin of VS Code Arduino Extension there is an option to set an output directory.
Note though that according to this it should not be in the workspace or subfolders.

So in arduino.json settings file add:  

"output": "../ArduinoOutput"