text: /* test the trylock interface */
  
  #include <stddef.h>
  
  #include "kernel.h"
  #include "pthread.h"
  #include "unit.h"
  
  int main(void)
  {
      pthread_mutex_t lock;
  
      pthread_mutex_init(&lock, NULL);
  
      if (pthread_mutex_lock(&lock))
          TEST_EXIT(1);
      printk("mutex is now locked...\n");
      if (!pthread_mutex_trylock(&lock))
          TEST_EXIT(1);
      printk("tried to lock a locked mutex...\n");
      if (pthread_mutex_unlock(&lock))
          TEST_EXIT(1);
      printk("mutex unlocked, trylock should succeed...\n");
      if (pthread_mutex_trylock(&lock))
          TEST_EXIT(1);
  
      TEST_EXIT(0);
  }
  