102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
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#include <rtthread.h>
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#define THREAD_PRIORITY 25
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#define THREAD_TIMESLICE 5
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/* 指向信号量的指针 */
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static rt_sem_t dynamic_sem = RT_NULL;
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static char thread1_stack[1024];
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static struct rt_thread thread1;
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/* 线程1入口函数 */
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static void rt_thread1_entry(void *parameter)
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{
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static rt_uint8_t count = 0;
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while(1)
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{
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if(count <= 100)
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{
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count++; // 计数器递增
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}
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else
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{
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return; // 计数器大于100时退出线程
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}
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/* count 每计数 10 次，就释放一次信号量 */
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if(0 == (count % 10))
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{
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rt_kprintf("t1 release a dynamic semaphore.\n");
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rt_sem_release(dynamic_sem); // 释放信号量
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}
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}
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}
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static char thread2_stack[1024];
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static struct rt_thread thread2;
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/* 线程2入口函数 */
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static void rt_thread2_entry(void *parameter)
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{
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static rt_err_t result;
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static rt_uint8_t number = 0;
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while(1)
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{
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/* 永久方式等待信号量，获取到信号量，则执行 number 自加的操作 */
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result = rt_sem_take(dynamic_sem, RT_WAITING_FOREVER);
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if (result != RT_EOK)
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{
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rt_kprintf("t2 take a dynamic semaphore, failed.\n");
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rt_sem_delete(dynamic_sem); // 删除信号量
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return;
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}
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else
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{
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number++; // 信号量获取成功，number 自加
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rt_kprintf("t2 take a dynamic semaphore. number = %d\n", number);
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}
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}
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}
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/* 信号量示例的初始化 */
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int semaphore_sample(void)
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{
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/* 创建一个动态信号量，初始值是 0 */
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dynamic_sem = rt_sem_create("dsem", 0, RT_IPC_FLAG_PRIO);
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if (dynamic_sem == RT_NULL)
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{
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rt_kprintf("create dynamic semaphore failed.\n");
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return -1;
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}
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else
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{
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rt_kprintf("create done. dynamic semaphore value = 0.\n");
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}
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/* 初始化并启动线程1 */
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rt_thread_init(&thread1,
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"thread1", /* 线程名称 */
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rt_thread1_entry, /* 线程入口函数 */
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RT_NULL, /* 入口函数参数 */
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&thread1_stack[0], /* 线程栈起始地址 */
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sizeof(thread1_stack), /* 线程栈大小 */
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THREAD_PRIORITY, THREAD_TIMESLICE); /* 线程优先级和时间片大小 */
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rt_thread_startup(&thread1);
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/* 初始化并启动线程2 */
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rt_thread_init(&thread2,
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"thread2", /* 线程名称 */
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rt_thread2_entry, /* 线程入口函数 */
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RT_NULL, /* 入口函数参数 */
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&thread2_stack[0], /* 线程栈起始地址 */
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sizeof(thread2_stack), /* 线程栈大小 */
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THREAD_PRIORITY-1, THREAD_TIMESLICE); /* 线程优先级和时间片大小 */
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rt_thread_startup(&thread2);
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return 0;
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}
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/* 导出到 msh 命令列表中 */
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MSH_CMD_EXPORT(semaphore_sample, semaphore sample);
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