Passing in additional parameters to Event Handler functions

[Chucky101]

I am trying to get access to a class member variable to expose whether the class is connected to Wifi or not.

I am currently registering the handler as shown below with the assumption that "this" will get passed into the handler in place of "event_data".

Code: [Select all] [Expand/Collapse]

1.  
2. esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, WifiEventHandler, this);
3.  

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When when this code runs it crashed and causes a LoadProhibited error.

Code: [Select all] [Expand/Collapse]

1.  
2. void WifiModule::WifiEventHandler(void *event_handler_arg, esp_event_base_t event_base, int32_t event_id, void *event_data)
3. {
4.     auto ThisWifiModuleReference = (WifiModule*)(event_data);
5.  
6.     std::cout << ThisWifiModuleReference->m_sSSID << std::endl;
7.  
8.     switch (event_id)
9.     {
10.     case WIFI_EVENT_STA_START:
11.         printf("WiFi connecting ... \n");
12.         //ThisWifiModuleReference->m_bWifiConnected = false;
13.         break;
14.     case WIFI_EVENT_STA_CONNECTED:
15.         printf("WiFi connected ... \n");
16.         //ThisWifiModuleReference->m_bWifiConnected = false;
17.         break;
18.     case WIFI_EVENT_STA_DISCONNECTED:
19.         printf("WiFi lost connection ... \n");
20.         //ThisWifiModuleReference->m_bWifiConnected = false;
21.         break;
22.     case IP_EVENT_STA_GOT_IP:
23.         printf("WiFi got IP ... \n\n");
24.         //ThisWifiModuleReference->m_bWifiConnected = true;
25.         break;
26.     default:
27.         break;
28.     }
29. }
30.  

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Still quite new to embedded programming so I would really appreciate an explanation as to why this would happen/how to fix it.

[boarchuz]

Close, but 'event_handler_arg' is your "this" pointer in this case, not 'event_data'.