[Sheepdog] [PATCH 5/5] logger: fix the vprintf() bug

[AndyChen]

2011/10/13 Liu Yuan <namei.unix at gmail.com>:
> On 10/13/2011 03:25 PM, AndyChen wrote:
>>
>> 2011/10/13 Liu Yuan<namei.unix at gmail.com>:
>>>
>>> On 10/13/2011 12:12 PM, AndyChen wrote:
>>>>>>
>>>>>> -       vprintf(SDOG_INFO "we create a new vdi, %d %s (%zd) %" PRIu64
>>>>>> ",
>>>>>> vid: %"
>>>>>> +       vprintf(SDOG_INFO, "we create a new vdi, %d %s (%zd) %" PRIu64
>>>>>> ", vid: %"
>>>>>>                PRIx32 ", base %" PRIx32 ", cur %" PRIx32 " \n",
>>>>>>                is_snapshot, name, strlen(name), size, *new_vid,
>>>>>> base_vid, cur_vid);
>>>>>>
>>>>>>        if (!copies) {
>>>>>> -               vprintf(SDOG_WARNING "qemu doesn't specify the
>>>>>> copies...
>>>>>> %d\n",
>>>>>> +               vprintf(SDOG_WARNING, "qemu doesn't specify the
>>>>>> copies... %d\n",
>>>>>>                        sys->nr_sobjs);
>>>>>>                copies = sys->nr_sobjs;
>>>>>>        }
>>>>>
>>>>> Why we need extra ',' in vprintf?
>>>>
>>>> it is not extra, now  vprintf() use log_write() which defined in
>>>> sheepdog/include/logger.h,
>>>> log_write() has log level parameter 'prio', but vrpintf() does not
>>>> parse the log level, use LOG_INFO default.
>>>> you mean use vprintf() such as use printk()?
>>>>
>>> I didn't get you meant. but the definition vprintf(fmt, args...) shows
>>> that
>>> 'fmt' is the constant char *,  so I don't think we need to place ','
>>> between
>>> two format strings. I look at the printk implementation in linux kernel,
>>> there is no such ',' between format strings either.
>>
>> here the vprintf defined by the sheep logger, not the standard library
>> function: vprintf(fmt, args...)
>
> #define vprintf(fmt, args...)                                           \
> do {                                                                    \
>        log_write(LOG_INFO, __func__, __LINE__, fmt, ##args);           \
> } while (0)
>
> extern void log_write(int prio, const char *func, int line, const char *fmt,
> ...)
>        __attribute__ ((format (printf, 4, 5)));
>
> So I think, it is safe to say that the type of 'fmt' in vprintf() is, const
> char *.
i think you are right

>
> Thanks,
> Yuan
>
>