mutex_sample.c

/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2018-08-24 yangjie the first version *//* * 程序清单：互斥锁例程 * * 互斥锁是一种保护共享资源的方法。当一个线程拥有互斥锁的时候， * 可以保护共享资源不被其他线程破坏。线程1对2个number分别进行加1操作 * 线程2也会对2个number分别进行加1操作。使用互斥量保证2个number值保持一致 */#include <rtthread.h>#define THREAD_PRIORITY 8#define THREAD_TIMESLICE 5/* 指向互斥量的指针 */static rt_mutex_t dynamic_mutex = RT_NULL;static rt_uint8_t number1, number2 = 0;ALIGN(RT_ALIGN_SIZE)static char thread1_stack[1024];static struct rt_thread thread1;static void rt_thread_entry1(void *parameter){ while (1) { /* 线程1获取到互斥量后，先后对number1、number2进行加1操作，然后释放互斥量 */ rt_mutex_take(dynamic_mutex, RT_WAITING_FOREVER); number1++; rt_thread_mdelay(10); number2++; rt_mutex_release(dynamic_mutex); }}ALIGN(RT_ALIGN_SIZE)static char thread2_stack[1024];static struct rt_thread thread2;static void rt_thread_entry2(void *parameter){ while (1) { /* 线程2获取到互斥量后，检查number1、number2的值是否相同，相同则表示mutex起到了锁的作用 */ rt_mutex_take(dynamic_mutex, RT_WAITING_FOREVER); if (number1 != number2) { rt_kprintf("not protect.number1 = %d, mumber2 = %d \n", number1, number2); } else { rt_kprintf("mutex protect ,number1 = mumber2 is %d\n", number1); } number1++; number2++; rt_mutex_release(dynamic_mutex); if (number1 >= 50) return; }}/* 互斥量示例的初始化 */int mutex_sample(void){ /* 创建一个动态互斥量 */ dynamic_mutex = rt_mutex_create("dmutex", RT_IPC_FLAG_FIFO); if (dynamic_mutex == RT_NULL) { rt_kprintf("create dynamic mutex failed.\n"); return -1; } rt_thread_init(&thread1, "thread1", rt_thread_entry1, RT_NULL, &thread1_stack[0], sizeof(thread1_stack), THREAD_PRIORITY, THREAD_TIMESLICE); rt_thread_startup(&thread1); rt_thread_init(&thread2, "thread2", rt_thread_entry2, RT_NULL, &thread2_stack[0], sizeof(thread2_stack), THREAD_PRIORITY - 1, THREAD_TIMESLICE); rt_thread_startup(&thread2); return 0;}/* 导出到 msh 命令列表中 */MSH_CMD_EXPORT(mutex_sample, mutex sample);