IBTL_PRINT_BUF_LEN
len += vsnprintf(msg_ptr, IBTL_PRINT_BUF_LEN - len - 2, fmt, ap);
len = min(len, IBTL_PRINT_BUF_LEN - 2);
static char ibtf_print_buf[IBTL_PRINT_BUF_LEN];