printf_verbose("Writer delay : %lu loops.\n", wdelay);
printf_verbose("Reader duration : %lu loops.\n", rduration);
printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
printf_verbose("Writer delay : %lu loops.\n", wdelay);
printf_verbose("Reader duration : %lu loops.\n", rduration);
printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",