# Watchdog Usage Example<a name="EN-US_TOPIC_0000001052657651"></a>

This example provides a complete process for using a watchdog.

In this example, open a watchdog, set the timeout duration, and start the watchdog.

-   Feed the watchdog periodically to ensure that the system is not reset due to timer expiry.
-   Stop feeding the watchdog and check whether the system is reset after the timer expires.

Example:

```
#include "watchdog_if.h"
#include "hdf_log.h"
#include "osal_irq.h"
#include "osal_time.h"

#define WATCHDOG_TEST_TIMEOUT     2
#define WATCHDOG_TEST_FEED_TIME   6

static int32_t TestCaseWatchdog(void)
{
    int32_t i;
    int32_t ret;
    uint32_t timeout;
    DevHandle handle = NULL;

    /* Open watchdog 0. */
    handle = WatchdogOpen(0);
    if (handle == NULL) {
        HDF_LOGE("Open watchdog fail!");
        return -1;
    }

    /* Set the timeout duration. */
    ret = WatchdogSetTimeout(handle, WATCHDOG_TEST_TIMEOUT);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: set timeout fail! ret:%d\n", __func__, ret);
        WatchdogClose(handle);
        return ret;
    }

    /* Obtain the configured timeout duration. */
    ret = WatchdogGetTimeout(handle, &timeout);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: get timeout fail! ret:%d\n", __func__, ret);
        WatchdogClose(handle);
        return ret;
    }
    HDF_LOGI("%s: read timeout back:%u\n", __func__, timeout);

    /* Start the watchdog. The timer starts. */
    ret = WatchdogStart(handle);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: satrt fail! ret:%d\n", __func__, ret);
        WatchdogClose(handle);
        return ret;
    }

    /* Feed the watchdog every 1s. */
    for (i = 0; i < WATCHDOG_TEST_FEED_TIME; i++) {
        HDF_LOGE("%s: feeding watchdog %d times... \n", __func__, i);
        ret = WatchdogFeed(handle);
        if (ret != HDF_SUCCESS) {
            HDF_LOGE("%s: feed dog fail! ret:%d\n", __func__, ret);
            WatchdogClose(handle);
            return ret;
        }
        OsalSleep(1);
    }
    /* Because the interval for feeding the watchdog is shorter than the timeout duration, the system does not reset, and logs can be printed normally. */
    HDF_LOGE("%s: no reset ... feeding test OK!!!\n", __func__);

    /* Enable the timer to expire by stopping feeding the watchdog. */
    for (i = 0; i < WATCHDOG_TEST_FEED_TIME; i++) {
        HDF_LOGE("%s: watiting dog buck %d times... \n", __func__, i);
        OsalSleep(1);
    }

    /* The system resets when the timer expires. If the code is correct, the log below is not displayed. */
    HDF_LOGE("%s: dog has't buck!!! \n", __func__, i);
    WatchdogClose(handle);
    return -1;
}
```