Date: Sun, 23 Jan 2005 16:30:24 +0200 From: Giorgos Keramidas <keramida@freebsd.org> To: Andrey Chernov <ache@nagual.pp.ru>, Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>, current@freebsd.org Subject: Re: Implementation errors in strtol() Message-ID: <20050123143024.GA28604@gothmog.gr> In-Reply-To: <20050122171743.GB39943@nagual.pp.ru> References: <20050121201400.GQ30862@uriah.heep.sax.de> <20050121221156.GA21459@nagual.pp.ru> <20050120192324.GA30862@uriah.heep.sax.de> <20050120205501.GA69123@nagual.pp.ru> <20050120211449.GC30862@uriah.heep.sax.de> <20050120214406.GA70088@nagual.pp.ru> <20050120222137.GE30862@uriah.heep.sax.de> <20050121230949.GA34313@VARK.MIT.EDU> <20050122113015.GV30862@uriah.heep.sax.de> <20050122171743.GB39943@nagual.pp.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2005-01-22 20:17, Andrey Chernov <ache@nagual.pp.ru> wrote:
> On Sat, Jan 22, 2005 at 12:30:15PM +0100, Joerg Wunsch wrote:
> > Nope. Just think about it: code which doesn't take this feature into
> > account needs to check for conversion errors by means of verifying
> > endptr. It simply wouldn't care about errno at all, except for
> > possibly checking for overflows -- which only needs to be verified
> > after it is already clear from checking endptr that the conversion was
> > OK. Thus, errno could not possibly be EINVAL anymore in that case.
>
> I know portable way of doing that. You describe one case from two. The
> another case you miss is more indirect: portable application which set
> "errno = 0" before calling strtol() to detect overflows (it is only
> method) even after checking that endptr moved can't check just
>
> if (errno) { ... }
>
> but must check
>
> if (errno == ERANGE) { ... }
>
> instead.
Hi Andrey,
Why would checking for explicit errno values be necessary? IIRC, after
a few emails I had exchanged with Dima Dorfman a few months ago,
checking for endptr *and* errno != 0 was ok.
Something like this was what we had come up with:
char *optarg, *endp;
long val;
errno = 0;
val = strtol(optarg, &endp, 0);
if (*ep != '\0' && *optarg != '\0')
err(1, "Partially converted string: %s", optarg);
if (errno != 0)
err(1, "Other error");
> That is, what I mean, saying that portable application should consider
> _both_ cases.
Just to clarify this a bit, when you say "both cases" you mean "both
ERANGE and EINVAL", or "both endp/nptr _and_ errno being zero (because
it was explicitly set to zero before calling strtol())"?
- Giorgos
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050123143024.GA28604>