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

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/*
* 程序清单:静态信号量
*
* 这个例子中将创建一个静态信号量初始值为0 )及一个静态线程,在这个静态线程中
* 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"
/* 线程控制块及栈 */
static struct rt_thread thread;
static rt_uint8_t thread_stack[THREAD_STACK_SIZE];
/* 信号量控制块 */
static struct rt_semaphore sem;
/* 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();
/* 试图持有信号量最大等待10个OS Tick后返回 */
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);
tc_done(TC_STAT_FAILED);
rt_sem_detach(&sem);
return;
}
rt_kprintf("take semaphore timeout\n");
}
else
{
/* 因为没有其他地方是否信号量,所以不应该成功持有信号量,否则测试失败 */
tc_done(TC_STAT_FAILED);
rt_sem_detach(&sem);
return;
}
/* 释放一次信号量 */
rt_sem_release(&sem);
/* 永久等待方式持有信号量 */
result = rt_sem_take(&sem, RT_WAITING_FOREVER);
if (result != RT_EOK)
{
/* 不成功则测试失败 */
tc_done(TC_STAT_FAILED);
rt_sem_detach(&sem);
return;
}
/* 测试通过 */
tc_done(TC_STAT_PASSED);
/* 脱离信号量对象 */
rt_sem_detach(&sem);
}
int semaphore_static_init(void)
{
rt_err_t result;
/* 初始化信号量初始值是0 */
result = rt_sem_init(&sem, "sem", 0, RT_IPC_FLAG_FIFO);
if (result != RT_EOK)
{
tc_stat(TC_STAT_END | TC_STAT_FAILED);
return 0;
}
/* 初始化线程1 */
result = rt_thread_init(&thread, "thread", /* 线程名thread */
thread_entry, RT_NULL, /* 线程的入口是thread_entry入口参数是RT_NULL*/
&thread_stack[0], sizeof(thread_stack), /* 线程栈是thread_stack */
THREAD_PRIORITY, 10);
if (result == RT_EOK) /* 如果返回正确启动线程1 */
rt_thread_startup(&thread);
else
tc_stat(TC_STAT_END | TC_STAT_FAILED);
return 0;
}
#ifdef RT_USING_TC
static void _tc_cleanup(void)
{
/* 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();
/* 执行线程脱离 */
if (thread.stat != RT_THREAD_CLOSE)
{
rt_thread_detach(&thread);
/* 执行信号量对象脱离 */
rt_sem_detach(&sem);
}
/* 调度器解锁 */
rt_exit_critical();
/* 设置TestCase状态 */
tc_done(TC_STAT_PASSED);
}
int _tc_semaphore_static(void)
{
/* 设置TestCase清理回调函数 */
tc_cleanup(_tc_cleanup);
semaphore_static_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_static, a static semaphore example);
#else
/* 用户应用入口 */
int rt_application_init(void)
{
semaphore_static_init();
return 0;
}
#endif