python:SIGALRM的Windows等效项

new9mtju  于 2023-01-29  发布在  Python
关注(0)|答案(2)|浏览(265)

我请了一个室内设计师:

def timed_out(timeout):
    def decorate(f):
        if not hasattr(signal, "SIGALRM"):
            return f

        def handler(signum, frame):
            raise TimedOutExc()

        @functools.wraps(f)
        def new_f(*args, **kwargs):
            old = signal.signal(signal.SIGALRM, handler)
            signal.alarm(timeout)
            try:
                result = f(*args, **kwargs)
            finally:
                signal.signal(signal.SIGALRM, old)
            signal.alarm(0)
            return result

        new_f.func_name = f.func_name
        return new_f

    return decorate

这段代码只在linux上运行,但是和windows一样,没有SIGALRM。让这段代码在Windows上运行的最简单的方法是什么?

ds97pgxw

ds97pgxw1#

这不是很漂亮,但我必须做一些类似的跨平台的方式,我想出了使用一个单独的线程。基于信号的系统并不能在所有平台上可靠地工作。
此类的使用可以 Package 在装饰器中,或者做成with上下文处理程序。
YMMV公司。

#!/usr/bin/env python2.7
import time, threading

class Ticker(threading.Thread):
  """A very simple thread that merely blocks for :attr:`interval` and sets a
  :class:`threading.Event` when the :attr:`interval` has elapsed. It then waits
  for the caller to unset this event before looping again.

  Example use::

    t = Ticker(1.0) # make a ticker
    t.start() # start the ticker in a new thread
    try:
      while t.evt.wait(): # hang out til the time has elapsed
        t.evt.clear() # tell the ticker to loop again
        print time.time(), "FIRING!"
    except:
      t.stop() # tell the thread to stop
      t.join() # wait til the thread actually dies

  """
  # SIGALRM based timing proved to be unreliable on various python installs,
  # so we use a simple thread that blocks on sleep and sets a threading.Event
  # when the timer expires, it does this forever.
  def __init__(self, interval):
    super(Ticker, self).__init__()
    self.interval = interval
    self.evt = threading.Event()
    self.evt.clear()
    self.should_run = threading.Event()
    self.should_run.set()

  def stop(self):
    """Stop the this thread. You probably want to call :meth:`join` immediately
    afterwards
    """
    self.should_run.clear()

  def consume(self):
    was_set = self.evt.is_set()
    if was_set:
      self.evt.clear()
    return was_set

  def run(self):
    """The internal main method of this thread. Block for :attr:`interval`
    seconds before setting :attr:`Ticker.evt`

    .. warning::
      Do not call this directly!  Instead call :meth:`start`.
    """
    while self.should_run.is_set():
      time.sleep(self.interval)
      self.evt.set()
vq8itlhq

vq8itlhq2#

此答案仅在Cygwin中有效。

...它可能不再与最新版本的Cygwin一起工作...

我发现这个timeout-decorator代码也非常方便。(我最初在这个问题的答案中找到它:如何限制函数调用的执行时间?)
为了让它在Windows上工作,我使用了随Cygwin一起安装的Python。
我运行setup-x86_64.exe,然后从Python文件夹中选择python3包(或者,如果您更喜欢Python 2,选择python包)。
为了将python3重命名为python 2,我定义了别名

alias python=python3

从Cygwin命令提示符。因为我不经常使用这个功能,我可能不会把它放在.bashrc或任何东西。
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