python中stop_thread_为什么pythonthreading.Thread对。。
。
完全可以实现如下⽰例代码所⽰的Thread.stop⽅法：import threading
import sys
class StopThread(StopIteration): pass
threading.SystemExit = SystemExit, StopThread
class Thread2(threading.Thread):
def stop(self):
self.__stop = True
def _bootstrap(self):
if threading._trace_hook is not None:
raise ValueError('Cannot run thread with tracing!')
self.__stop = False
sys.settrace(self.__trace)
super()._bootstrap()
def __trace(self, frame, event, arg):
if self.__stop:
raise StopThread()
return self.__trace
class Thread3(threading.Thread):
def _bootstrap(self, stop_thread=False):
def stop():
nonlocal stop_thread
stop_thread = True
self.stop = stop
def tracer(*_):
为什么使用bootstrap?if stop_thread:
raise StopThread()
return tracer
sys.settrace(tracer)
super()._bootstrap()
>>>>>>>>>>>>>>>>
import time
def main():
test = Thread2(target=printer)
test.start()
time.sleep(1)
test.stop()
test.join()
def printer():
while True:
print(time.time() % 1)
time.sleep(0.1)
if __name__ == '__main__':
main()
Thread3类运⾏代码的速度似乎⽐Thread2类3%。
附录：
充分了解Python的C API和ctypes模块的使⽤，可以编写⼀种更有效的⽅法来在需要时停⽌线程。使⽤sys.settrace的问题是跟踪函数在每条指令之后运⾏。如果在需要中⽌的线程上引发异步异常，则不会产⽣执⾏速度惩罚。以下代码在这⽅⾯提供了⼀些灵活性：#!
/usr/bin/env python3
import _thread
import ctypes as _ctypes
import threading as _threading
_PyThreadState_SetAsyncExc = _ctypes.pythonapi.PyThreadState_SetAsyncExc
# noinspection SpellCheckingInspection
_PyThreadState_SetAsyncExc.argtypes = _ctypes.c_ulong, _ctypes.py_object
_stype = _ctypes.c_int
# noinspection PyUnreachableCode
if __debug__:
# noinspection PyShadowingBuiltins
def _set_async_exc(id, exc):
if not isinstance(id, int):
raise TypeError(f'{id!r} not an int instance')
if not isinstance(exc, type):
raise TypeError(f'{exc!r} not a type instance')
if not issubclass(exc, BaseException):
raise SystemError(f'{exc!r} not a BaseException subclass')
return _PyThreadState_SetAsyncExc(id, exc)
else:
_set_async_exc = _PyThreadState_SetAsyncExc # noinspection PyShadowingBuiltins
def set_async_exc(id, exc, *args):
if args:
class StateInfo(exc):
def __init__(self):
super().__init__(*args)
return _set_async_exc(id, StateInfo)
return _set_async_exc(id, exc)
def interrupt(ident=None):
if ident is None:
_thread.interrupt_main()
else:
set_async_exc(ident, KeyboardInterrupt)
# noinspection PyShadowingBuiltins
def exit(ident=None):
if ident is None:
_it()
else:
set_async_exc(ident, SystemExit)
class ThreadAbortException(SystemExit):
pass
class Thread(_threading.Thread):
def set_async_exc(self, exc, *args):
return set_async_exc(self.ident, exc, *args)
def interrupt(self):
self.set_async_exc(KeyboardInterrupt)
def exit(self):
self.set_async_exc(SystemExit)
def abort(self, *args):
self.set_async_exc(ThreadAbortException, *args)
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