How to read stdout from subprocess as it is being produced

[Alex]

Hi,

I have a Pyhon GUI application that launches subprocess.
I would like to read the subprocess' stdout as it is being produced
(show it in GUI), without hanging the GUI.

I guess threading will solve the no-hanging issue, but as far as I
searched for now, I've only seen how to read the stdout after
subprocess is finished.

Thanks!