How check if a process has finished but without waiting?-CodePudding

I'm doing a small project in python/tkinter and I have been looking for a way to check if a process has finished but "without waiting". I have tried with:

process = subprocess.Popen(command)
while process.poll() is None:
    print('Running!')
print('Finished!')

or:

process = subprocess.Popen(command)
stdoutdata, stderrdata = process.communicate()
print('Finished!')

Both codes execute the command and print "Finished!" when the process ends, but the main program freezes (waiting) and that's what I want to avoid. I need the GUI to stay functional while the process is running and then run some code right after it finishes. Any help?

CodePudding user response：

It's common that you use the Thread module for that purpose:

For example:

# import Thread
from threading import Thread
import time

# create a function that checks if the process has finished
process = True
def check():
    while process:
        print('Running')
        time.sleep(1) # here you can wait as much as you want without freezing the program
    else:
        print('Finished')

# call the function with the use of Thread
Thread(target=check).start()
# or if you want to keep a reference to it
t = Thread(target=check)
# you might also want to set thread daemon to True so as the Thread ends when the program closes
t.deamon = True
t.start()

This way when you do process=False the program will end and the output will show 'Finished'