在 python 多處理中的進程之間使用共享值終止循環

Question

一旦進程 2 將 var 的值設置為 0，我希望 function 1 中的循環終止

var=multiprocessing.Value('i',1) #Using this variable as a shared variable between the processes.

def function1():
 #Loops until value of var is changed to 0 by function or process2
    while True:
     print("Hello")
     if var.value==0:
         break

def function2():
    print("Sleep")
    time.sleep(2)
    var.value=0
    print(var.value)

if __name__ == '__main__':
    multiprocessing.Process(target=function1).start()
    multiprocessing.Process(target=function2).start()

Answer 1

您的示例有效，您是否在腳本的開頭放置了“導入時間”？

其他改進：在分配新值之前鎖定變量：

def function2():
    print("Sleep")
    time.sleep(2)
    with var.get_lock():
        var.value=0
    print(var.value)

並且不要在全球范圍內使用它。 最好在 function 中定義一個新的輸入變量。

最后一個例子：

#!/usr/bin/env python3

import multiprocessing, time

var=multiprocessing.Value('i',1) #Using this variable as a shared variable between the processes.

def function1(v):
 #Loops until value of var is changed to 0 by function or process2
    while True:
     print("Hello")
     if v.value==0:
         break

def function2(v):
    print("Sleep")
    time.sleep(2)
    with v.get_lock():
        v.value=0
    print(v.value)

if __name__ == '__main__':
    multiprocessing.Process(target=function1, args = [var]).start()
    multiprocessing.Process(target=function2, args = [var]).start()