Re: "man 3 vsprintf" : simple bug in EXAMPLE section

[walter harms <wharms-fPG8STNUNVg@public.gmane.org>]

hi Zhen Ren,
i tried to create a more simple example. Do you think this is more
helpful for you ?

re,
 wh

char *
make_message2 (const char *fmt, ...)
{
  int n,size = 0;
  char *p = NULL;
  va_list ap;

  /* figure our required size */
  va_start (ap, fmt);
  size = vsnprintf (p, size, fmt, ap);
  va_end (ap);

  if (size < 0)
    return NULL;

  /* leave room for \0 */
  size++;
  p = malloc (size);
  if (p == NULL)
    return NULL;

  va_start (ap, fmt);
  n = vsnprintf (p, size, fmt, ap);
  va_end (ap);

return p;
}


Am 27.03.2015 10:52, schrieb Zhen Ren:
> Hi Michael,
> 
> I'm so sorry for this negative report.
> 
> Yeah, you're right. It'll fall through,loop again,do "vsprintf" and return if done.
> 
> --
> Best regards,
> Eric, Ren
> HA team, SUSE
> 
> 
>>>>
>> Hello Zhen Ren, 
>>  
>> On 27 March 2015 at 06:27, Zhen Ren <zren-IBi9RG/b67k@public.gmane.org> wrote: 
>>> Hi, 
>>> There is simple bug in EXAMPLE section of "man 3 vsprintf". 
>>>
>>> Function will return nothing if  it steps into the last "else {}". 
>>>
>>> ------------------ example code ----------------- 
>>>  char * 
>>>        make_message(const char *fmt, ...) 
>>>        { 
>>>            int n; 
>>>            int size = 100;     /* Guess we need no more than 100 bytes */ 
>>>            char *p, *np; 
>>>            va_list ap; 
>>> . 
>>> .cut off 
>>> . 
>>>                np = realloc(p, size); 
>>>                if (np == NULL) { 
>>>                    free(p); 
>>>                    return NULL; 
>>>                } else { 
>>>                    p = np; 
>>> +                return p; 
>>>                } 
>>>            } 
>>>        } 
>>  
>> I have not looked too closely at the code, but the above report 
>> appears incorrect to me. The function should NOT be returning at that 
>> point. It should be falling through and then round the loop once more. 
>> If I've missed something, could you elaborate a little more on the 
>> problem, please? 
>>  
>> Cheers, 
>>  
>> Michael 
>>  
>>  
> 
> 
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