CODEWITHSUNDEEP
pythonexitrestartsysos.system
JueK3y
JueK3y

Reputation: 317

Python: Restart script and exit it after function does not work

After a run, the user is asked whether he wants to end the programme [with sys.exit()] or restart it [os.system('main.py')].
If he restarts the programme, the programme will run through until he can decide again whether to restart or exit.
If the user then wants to end the programme, however, this is not possible, the programme is restarted anyway.
Also quit() or exit() do not work.

This is the prompt that asks the user to restart or quit:

while (res := input("Do you want to play again [1] oder exit[2]?\n").lower()) not in {"1", "2"}:
    pass
if res == "1":
    os.system('main.py')
else:
    end_game = True  # Stops the loop, but is not necessary
    print("Sys.exit game")
    sys.exit(0)

When I use subprocess.call(sys.executable + ' "' + os.path.realpath(__file__) + '"'),
exiting the program works, but the program is not really restarted [variables set to 0 at the beginning are not at 0].

Small note, the reboot will restart another py file (main.py), which is the main file, with the following content:

class main:
    game_logic()

if __name__ == '__main__':
    main()

game_logic() is the function from the other Py file in which the query for restarting and exiting is.

Upvotes: 0

Views: 2860

Answers (2)

JueK3y
JueK3y

Reputation: 317

I have been able to answer this question myself in the meantime.
I have done the following:
game_logic() is started via another py file (main.py).
At the restart which is executed within the game_logic() with os.system('main.py'), the current py file containing game_logic() is not terminated.
So if the main.py file is restarted, I have the file containing the game_logic() terminate afterwards.
It looks like this:

import os
import sys 

while (res := input("Do you want to play again [1] oder exit[2]?\n").lower()) not in {"1", "2"}:
    pass
if res == "1":
    os.system('main.py')
    exit()
else:
    exit()

Upvotes: 0

Cristian
Cristian

Reputation: 171

import os
import sys 

while (res := input("Do you want to play again [1] oder exit[2]?\n").lower()) not in {"1", "2"}:
    pass
if res == "1":
    python = sys.executable
    os.execl(python, python, * sys.argv)
else:
    end_game = True  # Stops the loop, but is not necessary
    print("Sys.exit game")
    sys.exit(0)

and

class main:
    game_logic()

if __name__ == '__main__':
    main()

The example above should work for you. You should use os.execl(...) instead of os.system(...). The last one creates new processes recursively and could cause an out of memory problem. You shouldn't create new processes, instead you want to replace the current process with a new one. This could be done with execl() or other calls from exec family.

To understand it properly, you may want to look here. It referes to C language, but it is kind of the same, because Python is wrapping around native calls.

Like all of the exec functions, execv replaces the calling process image with a new process image. This has the effect of running a new progam with the process ID of the calling process. Note that a new process is not started; the new process image simply overlays the original process image. The execv function is most commonly used to overlay a process image that has been created by a call to the fork function.

Upvotes: 1

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