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RIOT/tests/pthread_condition_variable/main.c 2 KB
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  /*
   * Copyright (C) 2014 Hamburg University of Applied Sciences (HAW)
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup tests
   * @{
   *
   * @file
   * @brief   simple condition variable test application
   *
   * @author  Martin Landsmann <martin.landsmann@haw-hamburg.de>
   *
   * @}
   */
  
  #include <stdio.h>
  #include "pthread.h"
  #include "thread.h"
  
  static mutex_t mutex = MUTEX_INIT;
  static pthread_cond_t cv;
  static volatile int is_finished;
  static volatile long count;
  static volatile long expected_value;
  static char stack[THREAD_STACKSIZE_MAIN];
  
  /**
   * @brief   This thread tries to lock the mutex to enter the critical section.
   *          Then it signals one waiting thread to check the condition and it goes to sleep again
   *          If is_finished is set to 1 second_thread ends
   */
  static void *second_thread(void *arg)
  {
      (void) arg;
      while (1) {
          mutex_lock(&mutex);
  
          if (is_finished == 1) {
              break;
          }
  
          pthread_cond_signal(&cv);
          mutex_unlock_and_sleep(&mutex);
      }
      return NULL;
  }
  
  int main(void)
  {
      count = 0;
      is_finished = 0;
      expected_value = 1000ul * 1000ul;
      pthread_cond_init(&cv, NULL);
  
      kernel_pid_t pid = thread_create(stack,sizeof(stack), THREAD_PRIORITY_MAIN - 1,
                                       THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
                                       second_thread, NULL, "second_thread");
  
      while (1) {
          mutex_lock(&mutex);
          thread_wakeup(pid);
          count++;
  
          if ((count % 100000) == 0) {
              printf("Still alive alternated [count: %ldk] times.\n", count / 1000);
          }
  
          if (count == expected_value) {
              puts("condition fulfilled.");
              is_finished = 1;
              mutex_unlock(&mutex);
              return 0;
          }
  
          pthread_cond_wait(&cv, &mutex);
          mutex_unlock(&mutex);
      }
  }