Python：The “freeze_support()“ line can be omitted if the program is not going to be frozen
该异常在windows执行python多进程时出现
完整的报错信息
Traceback (most recent call last):
File "" , line 1, in <module>
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 105, in spawn_main
exitcode = _main(fd)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 114, in _main
prepare(preparation_data)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 225, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
run_name="__mp_main__")
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 263, in run_path
Traceback (most recent call last):
File "" , line 1, in <module>
pkg_name=pkg_name, script_name=fname)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 85, in _run_code
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 105, in spawn_main
exec(code, run_globals)
File "D:\program\PythonProgram\test02.py", line 20, in <module>
process1.start()
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\process.py", line 112, in start
exitcode = _main(fd)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 114, in _main
self._popen = self._Popen(self)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\context.py", line 223, in _Popen
prepare(preparation_data)
return _default_context.get_context().Process._Popen(process_obj) File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 225, in prepare
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\context.py", line 322, in _Popen
return Popen(process_obj)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\popen_spawn_win32.py", line 46, in __init__
_fixup_main_from_path(data['init_main_from_path'])
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
prep_data = spawn.get_preparation_data(process_obj._name)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
_check_not_importing_main()
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
run_name="__mp_main__")
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 263, in run_path
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.
pkg_name=pkg_name, script_name=fname)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "D:\program\PythonProgram\test02.py", line 20, in
process1.start()
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\process.py", line 112, in start
self._popen = self._Popen(self)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\context.py", line 223, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\context.py", line 322, in _Popen
return Popen(process_obj)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\popen_spawn_win32.py", line 46, in __init__
prep_data = spawn.get_preparation_data(process_obj._name)
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
_check_not_importing_main()
File "D:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\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.
解决方法：
在main中加入
if __name__ == '__main__':
#你的代码
原因：
start方法产生了一个新的python进程，如果不用if保护创建代码则子进程拷贝父进程的资源而重新加载进程(windows平台不支持pyhon中的一项默认设置，详:https://mxnet.apache.org/versions/1.2.1/_modules/mxnet/gluon/data/dataloader.html)以此循环，直到程序崩溃