Bug#2906: Inconsistency in libc.info re snprintf

[Ian Jackson <ian@chiark.chu.cam.ac.uk>]

Package: glibcdoc
Version: 0.06-1

In the node `Formatted output functions':

 - Function: int snprintf (char *S, size_t SIZE, const char *TEMPLATE,
          ...)
...
     The return value is the number of characters stored, not including
     the terminating null.  If this value equals `SIZE - 1', then there
     was not enough space in S for all the output.  You should try
     again with a bigger output string.  Here is an example of doing
     this:
...
          while (1)
              {
                /* Try to print in the allocated space. */
                int nchars = snprintf (buffer, size,
                                       "value of %s is %s",
                                       name, value);
                /* If that worked, return the string. */
                if (nchars < size)
                  return buffer;
                /* Else try again with twice as much space. */
                size *= 2;
                buffer = (char *) xrealloc (size, buffer);
              }
          }

As you can see, in the example it assumes that failure is indicated by
nchars == size.  The ambiguity cannot be resolved from the rest of the
manpage, because it doesn't say whether snprintf still produces a
terminating null when it fails through lack of space.

Ian.