Using python thread as a plain object

Question

If i define a python thread extending threading.Thread class and overriding run I can then invoke run() instead of start() and use it in the caller thread instead of a separate one.

i.e.

class MyThread(threading.thread):
    def run(self):
        while condition():
            do_something()

this code (1) will execute "run" method this in a separate thread

t = MyThread()
t.start()

this code (2) will execute "run" method in the current thread

t = MyThread()
t.run()

Are there any practical disadvantages in using this approach in writing code that can be executed in either way? Could invoking directly the "run" of a Thread object cause memory problems, performance issues or some other unpredictable behavior?

In other words, what are the differences (if any notable, i guess some more memory will be allocated but It should be negligible) between invoking the code (2) on MyThread class and another identical class that extends "object" instead of "threading.Tread"

I guess that some (if any) of the more low level differences might depend on the interpreter. In case this is relevant i'm mainly interested in CPython 3.*

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

There will be no difference in the behavior of run when you're using the threading.Thread object, or an object of a threading.Thread's subclass, or an object of any other class that has the run method:

threading.Thread.start starts a new thread and then runs run in this thread.

run starts the activity in the calling thread, be it the main thread or another one.

If you run run in the main thread, the whole thread will be busy executing the task run is supposed to execute, and you won't be able to do anything until the task finishes.

That said, no, there will be no notable differences as the run method behaves just like any other method and is executed in the calling thread.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Aug 20, 2016 at 11:31

ForceBru

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Comments

Riccardo Cagnasso · Accepted Answer · 2016-08-23 23:55:23Z

0

I looked into the code implementing threading.Thread class in cpython 3. The init method simply assigns some variables and do not do anything that seems related to actually create a new thread. Therefore we can assume that it should be safe use a threading.Thread object in the proposed manner.

answered Aug 23, 2016 at 23:55

Riccardo Cagnasso

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