fix time() return value
@@ -174,23 +174,24 @@ double difftime (time_t tim1, time_t tim2)
*
* @param time_t * t the timestamp pointer, if not used, keep NULL.
*
- * @return time_t return timestamp current.
+ * @return The value ((time_t)-1) is returned if the calendar time is not available.
+ * If timer is not a NULL pointer, the return value is also stored in timer.
*
*/
RT_WEAK time_t time(time_t *t)
{
- time_t time_now = 0;
+ time_t time_now = ((time_t)-1); /* default is not available */
#ifdef RT_USING_RTC
static rt_device_t device = RT_NULL;
- /* optimization: find rtc device only first. */
+ /* optimization: find rtc device only first */
if (device == RT_NULL)
{
device = rt_device_find("rtc");
}
- /* read timestamp from RTC device. */
+ /* read timestamp from RTC device */
if (device != RT_NULL)
{
if (rt_device_open(device, 0) == RT_EOK)
