Process.start() Method

Method Name:

start

Method Signature:

start()

Return Value:

NoneType

Method Overview:

  • Calling start() method results in executing the process using the run method.
  • In case when run is empty the target parameter provided through the Process constructor will be used.
  • On a given Process instance start() method should be invoked only once.

Parameters:

Not Applicable

 

Example 1:

import multiprocessing as multiproc

 

class CustomProcess(multiproc.context.Process):

    def __init__(self, mq):

        multiproc.Process.__init__(self)

        self.mq = mq

       

    # Override run

    def run(self):

        self.mq.put("Message added by the child process")

 

if __name__=='__main__':

    print("Parent Process started")

    multiproc.set_start_method('spawn')

    mq = multiproc.Queue()

 

    childProcess = CustomProcess(mq)

    childProcess.start()

    childProcess.join()

   

    print(mq.get())

    print("Parent Process exiting")

 

Output:

Parent Process started

Message added by the child process

Parent Process exiting

Example 2:

 

import multiprocessing as multiproc

def processInst(mq):

    mq.put("Message added by the child process")

if __name__=='__main__':

    multiproc.set_start_method('forkserver')

    mq = multiproc.Queue()

    childProcess = multiproc.Process(target=processInst, args=(mq,))

    childProcess.start()

    childProcess.join()

   

    print(mq.get())

 

Output:

Message added by the child process

 


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