Question

Program that determines whether changing the current directory using os.chdir in one thread changes the current directory for a thread that already existed before the call to os.chdir My question is how do I get the value of a live thread?

import threading
import time
import os
class MyThread(threading.Thread):
def __init__(self, *args, **kw):
    threading.Thread.__init__(self, *args, **kw)
    self.sleeptime = 2
def run(self):        
    for i in range(self.sleeptime):
        for j in range(500000):
            k = j*j
        print(self.name, "finished pass", i)
    print(self.name, "finished after", self.sleeptime, "seconds")

bgthreads = threading.active_count()
threadOne = os.chdir("V:\workspace\Python4_Homework10")
threadTwo = os.chdir("V:\workspace")
threadThree = os.chdir("V:")
tt = [MyThread(threadOne), MyThread(threadTwo), MyThread(threadThree)]
for t in tt:    
   t.start()

print("Threads started")
while threading.active_count() > bgthreads:
    time.sleep(2)
    print("tick")

Answer 1

有点粗糙,但这样你的工作可能就完成了

#!/usr/bin/env python3

import os
import threading

def threadReporter(i,name):
    if name ==  Thread-changer : # crude, but gets the job done for this
        os.chdir( /tmp )
    print("{0} reports current pwd is: {1}".format(name,os.getcwd()))

if __name__ ==  __main__ :
    # create pre-chdir and changer Thread
    t_pre = threading.Thread(target=threadReporter, args=(1, Thread-pre ))
    t_changer = threading.Thread(target=threadReporter, args=(2, Thread-changer ))

    # start changer thread
    t_changer.start()
    # wait for it to finish
    t_changer.join()

    # start the thread that was created before the os.chdir() call
    t_pre.start()

    # create a thread after the os.chdir call and start it
    t_post = threading.Thread(target=threadReporter, args=(3, Thread-post ))
    t_post.start()

正如上文Gps已经指出的,当前的工作目录是进程-全球目录,而不是为每个可能生成/运行的线索分隔开来。因此,对于每个运行的线索来说,上面程序目前的工作目录报告是相等的,无论线索何时创建。在 os.chdir () 之后,为所有线索设置新的工作目录。

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