#Python process creation

In modern computer systems, multiple program instances can run simultaneously. For example, a user can work with Word while listening to music with a media player.

A running program instance is called a process. It is the basic unit of resource allocation by the operating system. Each process has its own independent memory space and system resources.

In Python, you create processes using the Process class from the multiprocessing module:

p = Process(target=entry_function, args=argument_list)

For example:

from multiprocessing import Process
import os
import time

# Entry function for the process
def worker(name):
    for _ in range(3):
        print(f'{os.getpid()}: My name is {name}')
        time.sleep(1)  # Process blocks for 1 second

if __name__ == '__main__':
    p1 = Process(target=worker, args=('worker1',))  # Create process
    p2 = Process(target=worker, args=('worker2',))
    p1.start()  # Start processes
    p2.start()
    p1.join()   # Wait for processes to finish
    p2.join()

Output:

45352: My name is worker1
94204: My name is worker2
45352: My name is worker1
94204: My name is worker2
45352: My name is worker1
94204: My name is worker2

Notes:

• The main process must check __name__ == '__main__' because Python creates child processes by re-importing the module. Without this check, infinite recursive process creation will occur.
• Process scheduling order is not guaranteed, so the output order is unpredictable.