Re: [Bug-gnulib] Re: snprintf

[Bruno Haible]

Paul Eggert wrote:
> > snprintf (char *str, size_t size, const char *format, ...)
> > {
> >   ...
> >   len = size;
> >   output = vasnprintf (str, &len, format, args);
>
> This assumes that STR is malloc-allocated, no?  I thought vasnprintf
> will reallocate STR if SIZE is too small.  But STR might point to
> static storage.

Good point. But actually vasnprintf will not reallocate STR, rather it will
allocate fresh memory, if SIZE is too small. The purpose is precisely so
that it can be used with a stack-allocated buffer:

   char buf[100];
   size_t len = sizeof (buf);
   char *output = vasnprintf (buf, &len, format, args);
   ...
   if (output != buf)
     free (output);

Bruno