[Solved] RuntimeError (note: full exception trace is shown but execution is paused at: ＜module＞)

Error using multiprocessing module:

from multiprocessing import Process

def hello():
    print('hello')

p = Process(target=hello)
p.start()

Change the code to:

from multiprocessing import Process, freeze_support, set_start_method

def hello():
    print('hello')

if __name__ == '__main__':
    p = Process(target=hello)
    p.start()

Which if __name__ == '__main__':role is to protect the program entry point , when a sub-process using open Process, Python interpreter into the current module, and invoke the hello method, using a simple intuitive test:

from multiprocessing import Process, freeze_support, set_start_method

def hello():
    print('hello')

print("!!!")

if __name__ == '__main__':
    p = Process(target=hello)
    p.start()

In this code, Print ("!!" is not a hello method. Let’s see the running result:

print("!!!") was called twice!!! So before generating a new process, be sure to add if__ name__ == '__ main__':！

Further, if you change print("!!!")to print(__name__), you will get the following results: