rt-thread-official/examples/kernel/semaphore_dynamic.c

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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
*
*/
/*
* 程序清单:动态信号量
*
* 这个例子中将创建一个动态信号量初始值为0 )及一个动态线程,在这个动态线程中
* 将试图采用超时方式去持有信号量,应该超时返回。然后这个线程释放一次信号量,并
* 在后面继续采用永久等待方式去持有信号量, 成功获得信号量后返回。
*/
#include <rtthread.h>
#include "tc_comm.h"
/* 指向线程控制块的指针 */
static rt_thread_t tid = RT_NULL;
/* 指向信号量的指针 */
static rt_sem_t sem = RT_NULL;
/* 线程入口 */
static void thread_entry(void* parameter)
{
rt_err_t result;
rt_tick_t tick;
/* 获得当前的OS Tick */
tick = rt_tick_get();
/* 试图持有一个信号量如果10个OS Tick依然没拿到则超时返回 */
result = rt_sem_take(sem, 10);
if (result == -RT_ETIMEOUT)
{
rt_tick_t new_tick = rt_tick_get();
/* 可以有两个 tick 的误差 */
if (new_tick - tick >= 12)
{
rt_kprintf("tick error to large: expect: 10, get %d\n",
new_tick - tick);
/* 如果失败,则测试失败 */
tc_done(TC_STAT_FAILED);
rt_sem_delete(sem);
return;
}
rt_kprintf("take semaphore timeout\n");
}
else
{
/* 因为并没释放信号量,应该是超时返回,否则测试失败 */
tc_done(TC_STAT_FAILED);
rt_sem_delete(sem);
return;
}
/* 释放一次信号量 */
rt_sem_release(sem);
/* 继续持有信号量,并永远等待直到持有到信号量 */
result = rt_sem_take(sem, RT_WAITING_FOREVER);
if (result != RT_EOK)
{
/* 返回不正确,测试失败 */
tc_done(TC_STAT_FAILED);
rt_sem_delete(sem);
return;
}
/* 测试成功 */
tc_done(TC_STAT_PASSED);
/* 删除信号量 */
rt_sem_delete(sem);
}
int semaphore_dynamic_init()
{
/* 创建一个信号量初始值是0 */
sem = rt_sem_create("sem", 0, RT_IPC_FLAG_PRIO);
if (sem == RT_NULL)
{
tc_stat(TC_STAT_END | TC_STAT_FAILED);
return 0;
}
/* 创建线程 */
tid = rt_thread_create("thread",
thread_entry, RT_NULL, /* 线程入口是thread_entry, 入口参数是RT_NULL */
THREAD_STACK_SIZE, THREAD_PRIORITY, THREAD_TIMESLICE);
if (tid != RT_NULL)
rt_thread_startup(tid);
else
tc_stat(TC_STAT_END | TC_STAT_FAILED);
return 0;
}
#ifdef RT_USING_TC
static void _tc_cleanup()
{
/* 调度器上锁,上锁后,将不再切换到其他线程,仅响应中断 */
rt_enter_critical();
if (sem)
{
rt_sem_delete(sem);
sem = RT_NULL;
}
/* 删除线程 */
if (tid != RT_NULL && tid->stat != RT_THREAD_CLOSE)
{
rt_thread_delete(tid);
}
/* 调度器解锁 */
rt_exit_critical();
/* 设置TestCase状态 */
tc_done(TC_STAT_PASSED);
}
int _tc_semaphore_dynamic()
{
/* 设置TestCase清理回调函数 */
tc_cleanup(_tc_cleanup);
semaphore_dynamic_init();
/* 返回TestCase运行的最长时间 */
return 100;
}
/* 输出函数命令到finsh shell中 */
FINSH_FUNCTION_EXPORT(_tc_semaphore_dynamic, a dynamic semaphore example);
#else
/* 用户应用入口 */
int rt_application_init()
{
semaphore_dynamic_init();
return 0;
}
#endif