[已解决]python多进程报错

foxiangzun

刚开始学 Python 的多任务，正在学多进程，可以下代码一允许，就有报错

# encoding=utf-8

import multiprocessing
import time

def dance():
    for i in range(3):
        print("跳舞~~~")
        time.sleep(0.2)

def sing():
    for i in range(3):
        print("唱歌~~~")
        time.sleep(0.2)

dance_process = multiprocessing.Process(target=dance)

dance_process.start()

sing()

然后控制台就出现了如下报错，百度没查到原因。。

E:\Python\pypath\Python\Python37\python.exe E:/Python/output/project01/src/test/test54.py
唱歌~~~
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 105, in spawn_main
    exitcode = _main(fd)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 114, in _main
    prepare(preparation_data)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 225, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
    run_name="__mp_main__")
  File "E:\Python\pypath\Python\Python37\lib\runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "E:\Python\pypath\Python\Python37\lib\runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "E:\Python\pypath\Python\Python37\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "E:\Python\output\project01\src\test\test54.py", line 18, in <module>
    dance_process.start()
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\process.py", line 112, in start
    self._popen = self._Popen(self)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\context.py", line 223, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\context.py", line 322, in _Popen
    return Popen(process_obj)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\popen_spawn_win32.py", line 46, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
    _check_not_importing_main()
  File "E:\Python\pypath\Python\Python37\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
    is not going to be frozen to produce an executable.''')
RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.
唱歌~~~
唱歌~~~

Process finished with exit code 0

可以看到，sing() 方法没有用进程来控制，是正常的，但是 dance() 用进程控制，就成了这样。。而且没有成功启动。。

最佳答案

月排行榜 / 总排行榜

isdkz

2022-4-23 21:30:56

报错提示中都告诉你了

RuntimeError:
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

# encoding=utf-8

import multiprocessing
import time

def dance():
    for i in range(3):
        print("跳舞~~~")
        time.sleep(0.2)

def sing():
    for i in range(3):
        print("唱歌~~~")
        time.sleep(0.2)

if __name__ == '__main__':                                     # 多进程要加上这个
    dance_process = multiprocessing.Process(target=dance)

    dance_process.start()

    sing()

跳转到最佳答案楼层

isdkz

报错提示中都告诉你了

RuntimeError:
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

# encoding=utf-8

import multiprocessing
import time

def dance():
    for i in range(3):
        print("跳舞~~~")
        time.sleep(0.2)

def sing():
    for i in range(3):
        print("唱歌~~~")
        time.sleep(0.2)

if __name__ == '__main__':                                     # 多进程要加上这个
    dance_process = multiprocessing.Process(target=dance)

    dance_process.start()

    sing()

foxiangzun

isdkz 发表于 2022-4-23 21:30
报错提示中都告诉你了

还真是这个原因。。报错里愣是没看懂这里的意思。。以为是多进程包里的 main 方法提示。。

感谢指点

isdkz

foxiangzun 发表于 2022-4-23 21:42
还真是这个原因。。报错里愣是没看懂这里的意思。。以为是多进程包里的 main 方法提示。。

...

你可以复制到翻译软件看看

foxiangzun

isdkz 发表于 2022-4-23 21:43
你可以复制到翻译软件看看

这一块上面的扔到了翻译软件里，下面也扔进了翻译软件里，唯独这一部分给忽略了。。