void print_stack_trace()
{
  void *array[200];
  size_t size;
  char **strings = NULL;
  size_t i;

  //use -rdynamic flag when compiling
  size = backtrace (array, 200);
  strings = backtrace_symbols (array, size);

  if ( strings ) {
          fprintf(stderr, "----------------------------------------\n");
          for (i = 0; i < size; i++)
               fprintf(stderr, "%s\n", strings[i]);

  free(strings);
  }
}