process join 28 29

1from multiprocessing import Process
2import os
3
4def info(title):
5    print(title)
6    print('module name:', __name__)
7    print('parent process:', os.getppid())
8    print('process id:', os.getpid())
9
10def f(name):
11    info('function f')
12    print('hello', name)
13
14if __name__ == '__main__':
15    info('main line')
16    p = Process(target=f, args=('bob',))
17    p.start()
18    p.join()

1from multiprocessing import Process
2
3def f(name):
4    print('hello', name)
5
6if __name__ == '__main__':
7    p = Process(target=f, args=('bob',))
8    p.start()
9    p.join()

1import multiprocessing as mp
2
3def foo(q):
4    q.put('hello')
5
6if __name__ == '__main__':
7    mp.set_start_method('spawn')
8    q = mp.Queue()
9    p = mp.Process(target=foo, args=(q,))
10    p.start()
11    print(q.get())
12    p.join()

1import multiprocessing as mp
2
3def foo(q):
4    q.put('hello')
5
6if __name__ == '__main__':
7    ctx = mp.get_context('spawn')
8    q = ctx.Queue()
9    p = ctx.Process(target=foo, args=(q,))
10    p.start()
11    print(q.get())
12    p.join()