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

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

quoted

quoted

quoted

Hello Zhen Ren, 
 
On 27 March 2015 at 06:27, Zhen Ren [off-list ref] wrote: 

quoted

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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