python3 window和linux两个不同操作系统创建进程的区别

# coding:utf-8
import os
import time
from multiprocessing import Process


def func():
    print("func start...")
    time.sleep(1)
    print("func end...")


print("程序开始了.")
p = Process(target=func,)
p.start()
print("程序结束了.")

运行结果:

程序开始了.
程序结束了.
程序开始了.
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 106, in spawn_main
    exitcode = _main(fd)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 115, in _main
    prepare(preparation_data)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 226, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 278, in _fixup_main_from_path
    run_name="__mp_main__")
  File "F:2019 pythonpython-3.4.3rc1lib unpy.py", line 240, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "F:2019 pythonpython-3.4.3rc1lib unpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "F:2019 pythonpython-3.4.3rc1lib unpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "F:2019老男孩周末26期day09课下练习1 window和linux的区别.py", line 15, in <module>
    p.start()
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingprocess.py", line 105, in start
    self._popen = self._Popen(self)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingcontext.py", line 212, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingcontext.py", line 313, in _Popen
    return Popen(process_obj)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingpopen_spawn_win32.py", line 34, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 144, in get_preparation_data
    _check_not_importing_main()
  File "F:2019 pythonpython-3.4.3rc1libmultiprocessingspawn.py", line 137, 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.

这是window操作系统运行下的结果.

解决方法就是将主程序放到if __name__ == '__main__':

# coding:utf-8
import os
import time
from multiprocessing import Process


def func():
    print("func start...")
    time.sleep(1)
    print("func end...")


if __name__ == '__main__':
    print("程序开始了.")
    p = Process(target=func,)
    p.start()
    print("程序结束了.")


# 程序开始了.
# 程序结束了.
# func start...
# func end...