How to pass self and 2 arguments to thread

Question

I'm simply trying to pass self and 2 other arguments to a thread, but I'm getting an error every time.

I tried following other samples, but nothing has worked so far.

class X:
    def start(self):
        newStartupThread = threading.Thread(target=self.launch, args=(t1_stop, 
            self.launchAdditionalParams))
        newStartupThread.name = "ClientLaunchThread%d" % 
            (self.launchAttemptCount+1)
        newStartupThread.daemon = True
        newStartupThread.start()


    def launch(self, test, additionalParams):
        pass

I'm getting this error:

TypeError: launch() takes at most 2 arguments (3 given)

**Edited the code to show that it is in a class

AKX · Accepted Answer · 2019-01-04T22:04:28.283

2

From the presence of self, I assume this is in a class.

import threading


class X:
    def start(self):
        t1_stop = 8
        self.launchAdditionalParams = {}

        newStartupThread = threading.Thread(
            target=self.launch,
            args=(t1_stop, self.launchAdditionalParams),
        )
        newStartupThread.name = "ClientLaunchThread"
        newStartupThread.daemon = True
        newStartupThread.start()

    def launch(self, test, additionalParams):
        print(locals())


x = X()
x.start()

works fine for me, outputting

{'additionalParams': {}, 'test': 8, 'self': <__main__.X object at 0x000001442938F438>}

edited Jan 04 '19 at 22:04

answered Jan 04 '19 at 21:48

AKX

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I did forget to show that its in a class. I edited the code to show the same. Using the lambda, I'm still getting the same error. – Snipe3000 Jan 04 '19 at 21:56
Oofp, I had actually forgotten the lambda from my example anyway. Anyway, I can't reproduce your original problem; see edit. – AKX Jan 04 '19 at 22:04
OK thanks, super odd that it doesn't work on my system. At least I now know Im not crazy. – Snipe3000 Jan 04 '19 at 22:40

Pika Supports Ukraine · Answer 2 · 2019-01-04T22:00:07.377

0

launch is a function, not a method. Only methods need the self argument. Just remove the self argument and it should work:

def launch(test, additionalParams):

If it is within a class, you have to do one of two things:

Call it only on instances of the class (someClass.launch(arg1, arg2))
Make it a static method by not including the self argument

edited Jan 04 '19 at 22:00

answered Jan 04 '19 at 21:42

Pika Supports Ukraine

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How to pass self and 2 arguments to thread

2 Answers2