【修改】由于 gettimeofday 函数依赖 rtc 设备才能实现，因此如果无法获取 rtc 设备应当断言

components/libc/compilers/armlibc/time.c

@@ -16,19 +16,16 @@ int gettimeofday(struct timeval *tp, void *ignore)
     rt_device_t device;
 
     device = rt_device_find("rtc");
-    if (device != RT_NULL)
-    {
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
-        if (tp != RT_NULL)
-        {
-            tp->tv_sec = time;
-            tp->tv_usec = 0;
-        }
+    RT_ASSERT(device != RT_NULL);
 
-        return time;
+    rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+    if (tp != RT_NULL)
+    {
+        tp->tv_sec = time;
+        tp->tv_usec = 0;
     }
 
-    return 0;
+    return time;
 }
 #endif