Wi-Fi reconnect handler

The code

Embedded C for Cortex-M. It compiles. There are 3 real bugs in it: the kind that pass a bench test and fail in the field.

static int retries;

static void wifi_event(void *arg, esp_event_base_t base,
                       int32_t id, void *data)
{
    if (base == WIFI_EVENT && id == WIFI_EVENT_STA_DISCONNECTED) {
        if (retries < 5) {
            vTaskDelay(pdMS_TO_TICKS(1000));
            esp_wifi_connect();
            retries++;
        }
    } else if (base == IP_EVENT && id == IP_EVENT_STA_GOT_IP) {
        mqtt_start();
    }
}

What an interviewer expects

• Point to each line you'd stop in a code review.
• Say what actually breaks: the failure mode, not just the rule it violates.
• Fix it, then defend the fix when asked the follow-up.

The bugs, reference fixes and the follow-up question are in the practice app, after you've tried it.

Companies that test this

Matched on the skills each company's embedded roles emphasise.

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