Nasty hack to raise exception for other threads

from future import print_function

import ctypes import threading import time

def async_raise(thread_obj, exception): """ Raises an exception inside an arbitrary active :class:~threading.Thread.

Parameters
----------
thread_obj : :class:`~threading.Thread`
    The target thread.
exception : ``Exception``
    The exception class to be raised.

Raises
------
ValueError
    The specified :class:`~threading.Thread` is not active.
SystemError
    The raise operation failed, the interpreter has been left in an inconsistent state.
"""
target_tid = thread_obj.ident
if target_tid not in {thread.ident for thread in threading.enumerate()}:
    raise ValueError('Invalid thread object, cannot find thread identity among currently active threads.')

affected_count = ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(target_tid), ctypes.py_object(exception))

if affected_count == 0:
    raise ValueError('Invalid thread identity, no thread has been affected.')
elif affected_count > 1:
    ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(target_tid), ctypes.c_long(0))
    raise SystemError("PyThreadState_SetAsyncExc failed, broke the interpreter state.")

if name == 'main':

def f():
    try:
        while True:
            time.sleep(1)
    finally:
        print("Exited")

t = threading.Thread(target=f)
t.start()
print("Thread started")
print(t.isAlive())
time.sleep(5)
async_raise(t, SystemExit)
t.join()
print(t.isAlive())