I was always wondering what happens if I run my script without compiling, assume it runs for ~30 minutes, and in the meantime I make some changes to the source code. What happens with my running script? Will it crash as soon as I save new source code or it will work till it’s done (with old source code of course)?
The result is a bit unpredictable. CINT sometimes goes back to the file to lookup the implementation of functions (in particular the first time a function is executed). So if you script contains a single function, you are pretty safe otherwise no.