Python threading daemon error when extending Thread class

Question

I’ve been trying to extend my Thread class to return something from a target function but I want to keep the daemon = True. The default daemon is False so I need to pass the True value into the Thread.__init__() and when I try: __init__() takes from 1 to 6 positional arguments but 7 were given
Here’s the code:

class Thread1(Thread):
    def __init__(self, group=None, target=None, name=None,
                 args=(), kwargs={}, daemon = None):
        Thread.__init__(self, group, target, name, args, kwargs, daemon)
        self._return = None

    def run(self):
        if self._target is not None:
            self._return = self._target(*self._args, **self._kwargs)
    def join(self, *args):
        Thread.join(self, *args)
        return self._return

I’ve tried to remove the self parameter but it doesn’t work then.

Asked By: sapkodas

||

Source

Answer 1

The Thread.__init__() method takes up to 6 arguments, but you are passing 7 arguments to it, including daemon. This is causing the error message you’re seeing.

To fix this issue, you can remove the daemon parameter from the Thread.__init__() method call and instead set the daemon attribute of the thread object after it has been created.

Here’s an updated version of your code:

class Thread1(Thread):
    def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
        super().__init__(group=group, target=target, name=name, args=args, kwargs=kwargs)
        self._return = None
        self.daemon = True

    def run(self):
        if self._target is not None:
            self._return = self._target(*self._args, **self._kwargs)

    def join(self, *args):
        super().join(*args)
        return self._return

Answered By: xitas

Python threading daemon error when extending Thread class

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