Re: [Valgrind-users] suppress warning repetition

[Ivo R. <iv...@iv...>]

2015-01-02 2:21 GMT+01:00 John Reiser <jr...@bi...>:

>
> If there is any doubt [you have at least 1% doubt] then you should replace
> all uses
> of sprintf with snprintf instead.  Using snprintf is not a fool-proof
> cure-all.
> If the length limit is reached then the result has no terminating '\0',
> so subsequent reads (such as via %s) might over-read the space for the
> result.
>
>
While I strongly agree with everything that John R. has written,
snprintf() actually *does* terminate the output buffer with terminating
'\0'.
See the POSIX specification [1] for snprintf():

"The *snprintf*() function shall be equivalent to *sprintf*(), with the
addition of the *n* argument which states the size of the buffer referred
to by *s*. If *n* is zero, nothing shall be written and *s* may be a null
pointer. Otherwise, output bytes beyond the *n*-1st shall be discarded
instead of being written to the array, and a null byte is written at the
end of the bytes actually written into the array."

and a discussion [2] about snprintf() on Windows.

I.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/fprintf.html
[2]
http://stackoverflow.com/questions/7706936/is-snprintf-always-null-terminating