线程和 MQTT 接收之间不共享全局变量 python

Question

主线程：

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect(Broker, 1883, 60)
client.on_log = on_log
client.loop_start()

global alarm
alarm = True

while True:        
    try:
        if alarm == True:
        ...

并且在函数中有变化变量：

def on_message(client, userdata, msg):
    message = str(msg.payload)
    if message.lower() == 'alarm off': alarm = False
    elif message.lower() == 'alarm on': alarm = True

它在函数和 Mainthread 中就像单独的变量一样工作，我找不到原因。

Answer 1

var 应该在 on_message 函数中标记为全局变量，而不是在您拥有它的地方。

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect(Broker, 1883, 60)
client.on_log = on_log
client.loop_start()

alarm = True

while True:        
    try:
        if alarm == True:
        ...

和

def on_message(client, userdata, msg):
    global alearm
    message = str(msg.payload)
    if message.lower() == 'alarm off': alarm = False
    elif message.lower() == 'alarm on': alarm = True

线程和 MQTT 接收之间不共享全局变量 python

global variable is not shared between thread and MQTT receive python

python

global

global-variables