注释LOG_D导致alarm 闹钟功能失效

发布于 2023-03-26 17:41:25 浏览：528 订阅该版

我最近调试alarm 闹钟好了，就想把LOG输出关掉（DBG_LVL由DBG_LOG改为DBG_INFO），结果奇怪的事情发生了，alarm 闹钟功能失效了。为了验证，我采用了以下三种方式验证：
1、DBG_LVL保持DBG_LOG，注释`LOG_D("%s", ctime(&now));`，结果alarm 闹钟功能失效；
2、DBG_LVL保持DBG_LOG，将`LOG_D("%s", ctime(&now));` 改为 `ctime(&now);` 结果alarm 闹钟功能失效；
3、在2的基础上，加了延时500ms； 结果alarm 闹钟功能失效；

代码如下：

```c
/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2023-02-19     59427       the first version
 */

#include <rtthread.h>
#include <rtdevice.h>
#include "alex.h"

#define DBG_TAG "alarm"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

#define THREAD_PRIORITY         18
#define THREAD_STACK_SIZE       1024
#define THREAD_TIMESLICE        5

#define RTC_NAME       "rtc"

static rt_thread_t tid1 = RT_NULL;

void user_alarm_callback(rt_alarm_t alarm, time_t timestamp)
{
    /* 释放信号量 */
    rt_sem_release(rtc_sem);
}

/* 线程的入口函数 */
static void alarm_entry(void *parameter)
{
    struct rt_alarm_setup setup;
    struct rt_alarm * alarm = RT_NULL;
    time_t now;
    struct tm p_tm;

rt_err_t ret = RT_EOK;

/* 设置日期 */
    ret = set_date(2023, 1, 1);
    if (ret != RT_EOK)
    {
        LOG_E("set RTC date failed");
        return;
    }

/* 设置时间 */
    ret = set_time(0, 0, 0);
    if (ret != RT_EOK)
    {
        LOG_E("set RTC time failed");
        return;
    }

/* 延时3秒 */
    rt_thread_mdelay(1000);

/* 获取时间 */
    now = time(RT_NULL);
    LOG_D("%s", ctime(&now));

/* 获取当前时间戳，并把下一秒时间设置为闹钟时间 */
    now = time(RT_NULL) + 2;
    gmtime_r(&now,&p_tm);

setup.flag = RT_ALARM_SECOND;
    setup.wktime.tm_year = p_tm.tm_year;
    setup.wktime.tm_mon = p_tm.tm_mon;
    setup.wktime.tm_mday = p_tm.tm_mday;
    setup.wktime.tm_wday = p_tm.tm_wday;
    setup.wktime.tm_hour = p_tm.tm_hour;
    setup.wktime.tm_min = p_tm.tm_min;
    setup.wktime.tm_sec = p_tm.tm_sec;

alarm = rt_alarm_create(user_alarm_callback, &setup);
    if(RT_NULL != alarm)
    {
        rt_alarm_start(alarm);
    }
}

/* 线程示例 */
int alarm_sample_start(void)
{
    /* 创建线程,入口是entry*/
    tid1 = rt_thread_create("alarm",
                            alarm_entry, RT_NULL,
                            THREAD_STACK_SIZE,
                            THREAD_PRIORITY, THREAD_TIMESLICE);

/* 如果获得线程控制块，启动这个线程 */
    if (tid1 != RT_NULL)
        rt_thread_startup(tid1);

return RT_EOK;
}

```