Ubuntu 10.04-Python multiprocessing-'module'对象没有属性'local'错误

Question

以下代码来自python 2.6手册。

from multiprocessing import Process
import os

def info(title):
    print(title)
    print('module name:', 'me')
    print('parent process:', os.getppid())
    print('process id:', os.getpid())

def f(name):
    info('function f')
    print('hello', name)

if __name__ == '__main__':
    info('main line')
    p = Process(target=f, args=('bob',))
    p.start()
    p.join()

这将创建以下堆栈跟踪：

Traceback (most recent call last):
  File "threading.py", line 1, in <module>
    from multiprocessing import Process
  File "/usr/lib/python2.6/multiprocessing/__init__.py", line 64, in <module>
    from multiprocessing.util import SUBDEBUG, SUBWARNING
  File "/usr/lib/python2.6/multiprocessing/util.py", line 287, in <module>
    class ForkAwareLocal(threading.local):
AttributeError: 'module' object has no attribute 'local'
Exception AttributeError: '_shutdown' in <module 'threading' from '/home/v0idnull/tmp/pythreads/threading.pyc'> ignored
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/lib/python2.6/multiprocessing/util.py", line 258, in _exit_function
    info('process shutting down')
TypeError: 'NoneType' object is not callable
Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/lib/python2.6/multiprocessing/util.py", line 258, in _exit_function
    info('process shutting down')
TypeError: 'NoneType' object is not callable

我完全不知道为什么发生这种情况，而google给我的帮助很少。

Answer 1

该代码可以在我的机器上正常运行：
Ubuntu 10.10，Python 2.6.6 64位。

但是您的错误实际上是因为您有一个名为“ threading.py”的文件，该文件是从中运行此代码的（请参阅堆栈跟踪详细信息）。这会导致名称空间不匹配，因为多处理模块需要“真实”线程模块。尝试将文件重命名为'threading.py'以外的名称，然后再次运行。

也...您发布的示例不是来自Python 2.6文档...而是来自Python 3.x文档。确保您正在阅读与您正在运行的版本相匹配的文档。