examples/nxflat/tests/mutex/mutex.c

/****************************************************************************
 * apps/examples/nxflat/tests/mutex/mutex.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

/****************************************************************************
 * Private Data
 ****************************************************************************/

static pthread_mutex_t mut;
static volatile int my_mutex = 0;
static unsigned long nloops[2] = {0, 0};
static unsigned long nerrors[2] = {0, 0};
static volatile bool bendoftest;

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/* NOTE: it is necessary for functions that are referred to by function pointers
 * pointer to be declared with global scope (at least for ARM).  Otherwise,
 * a relocation type that is not supported by NXFLAT is generated by GCC.
 */

void thread_func(void *parameter)
{
  int my_id  = (int)parameter;
  int my_ndx = my_id - 1;
  int i;

  /* Loop 20 times.  There is a 100 MS delay in the loop so this should
   * take about 2 seconds.  The main thread will stop this thread after
   * 2 seconds by setting bendoftest in any event.
   */

  for (i = 0; i < 20 && !bendoftest; i++)
    {
      if ((pthread_mutex_lock(&mut)) != 0)
        {
          printf("ERROR thread %d: pthread_mutex_lock failed\n", my_id);
        }

      if (my_mutex == 1)
        {
          printf("ERROR thread=%d: "
                 "my_mutex should be zero, instead my_mutex=%d\n",
                 my_id, my_mutex);
          nerrors[my_ndx]++;
        }

      my_mutex = 1;
      usleep(100000);
      my_mutex = 0;

      if ((pthread_mutex_unlock(&mut)) != 0)
        {
          printf("ERROR thread %d: pthread_mutex_unlock failed\n", my_id);
        }

      nloops[my_ndx]++;
    }
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

int main(int argc, char **argv)
{
  pthread_t thread1;
  pthread_t thread2;

  /* Initialize the mutex */

  pthread_mutex_init(&mut, NULL);

  /* Start two thread instances */

  printf("Starting thread 1\n");
  bendoftest = false;
  if ((pthread_create(&thread1, NULL, (void*)thread_func, (void *)1)) != 0)
    {
      fprintf(stderr, "Error in thread#1 creation\n");
    }

  printf("Starting thread 2\n");
  if ((pthread_create(&thread2, NULL, (void*)thread_func, (void*)2)) != 0)
    {
      fprintf(stderr, "Error in thread#2 creation\n");
    }

  /* Wait a bit for the threads to do their thing. */

  sleep(2);

  /* Then ask them politely to stop running */

  printf("Stopping threads\n");
  bendoftest = true;
  pthread_join(thread1, NULL);
  pthread_join(thread2, NULL);

  printf("\tThread1\tThread2\n");
  printf("Loops\t%lu\t%lu\n", nloops[0], nloops[1]);
  printf("Errors\t%lu\t%lu\n", nerrors[0], nerrors[1]);

  return 0;
}