我有兩個線程正在運行，我希望它們使用 threading.Condition() 在特定行相互等待。然而，似乎全局變量 v 不是全局的。它是每個線程的不同變量。這是最小可行產品：import threadinglock = threading.Condition()v = 0n = 2def barrier(): with lock: global v v =+ 1 print("v is increased to " + str(v)) if v == n: print("v is equal to n") lock.notifyAll() print("v equals n") v = 0 else: lock.wait()class ServerThread(threading.Thread): def __init__(self): threading.Thread.__init__(self) def run(self): print("before barrier") barrier() print("after barrier")for i in range(2): t = ServerThread() t.start()輸出是這樣的：before barrierv is increased to 1before barrierv is increased to 1但我希望 v 通過第二個線程增加到 2 以便可以通過障礙。怎么了？
1 回答
翻閱古今
TA貢獻1780條經驗 獲得超5個贊
您可以利用隊列在線程之間共享數據。我不確定此代碼是否會根據您的用例工作，但您可以執行以下操作：
import threading, queue
lock = threading.Condition()
q = queue.Queue()
q.put(0)
n = 2
def barrier():
with lock:
v_increase = q.get() + 1
q.put(v_increase)
print("v is increased to " + str(v_increase))
if v_increase == n:
print("v is equal to n")
lock.notifyAll()
print("v equals n")
q.get()
q.put(0)
else:
lock.wait()
class ServerThread(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
global v
print("before barrier")
barrier()
print("after barrier")
for i in range(2):
t = ServerThread()
t.start()
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