Method do_check

sql/sys_vars.h:1017–1059

    DBUG_ASSERT(size == sizeof(ulonglong));
  }
  bool do_check(THD *thd, set_var *var)
  {
    char buff[STRING_BUFFER_USUAL_SIZE];
    String str(buff, sizeof(buff), system_charset_info), *res;

    if (var->value->result_type() == STRING_RESULT)
    {
      if (!(res=var->value->val_str(&str)))
        return true;
      else
      {
        char *error;
        uint error_len;
        bool not_used;

        var->save_result.ulonglong_value=
              find_set(&typelib, res->ptr(), res->length(), NULL,
                      &error, &error_len, &not_used);
        /*
          note, we only issue an error if error_len > 0.
          That is even while empty (zero-length) values are considered
          errors by find_set(), these errors are ignored here
        */
        if (error_len)
        {
          ErrConvString err(error, error_len, res->charset());
          my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), name.str, err.ptr());
          return true;
        }
      }
    }
    else
    {
      longlong tmp=var->value->val_int();
      if ((tmp < 0 && ! var->value->unsigned_flag)
          || (ulonglong)tmp > MAX_SET(typelib.count))
        return true;
      else
        var->save_result.ulonglong_value= tmp;
    }

    return false;
  }
  bool session_update(THD *thd, set_var *var)
  {
    session_var(thd, ulonglong)= var->save_result.ulonglong_value;