Date: Fri, 21 Jan 2005 00:44:06 +0300 From: Andrey Chernov <ache@nagual.pp.ru> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: bde@FreeBSD.ORG Subject: Re: Implementation errors in strtol() Message-ID: <20050120214406.GA70088@nagual.pp.ru> In-Reply-To: <20050120211449.GC30862@uriah.heep.sax.de> References: <20050120192324.GA30862@uriah.heep.sax.de> <20050120205501.GA69123@nagual.pp.ru> <20050120211449.GC30862@uriah.heep.sax.de>
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On Thu, Jan 20, 2005 at 10:14:49PM +0100, Joerg Wunsch wrote:
> Yes, I know. Anyway, how could POSIX (or the Single UNIX
> Specification, for that matter) possibly contradict to the C standard?
There is common practice for both POSIX and SUS to extend errno values
beyond C standard, see lots of other functions. Personally I do not
research the reason of their decision, just point to the fact.
> ``The value of errno is zero at program startup, but is never set to
> zero by any library function.170) The value of errno may be set to
^^^^^^^^^^^^^^^^
> nonzero by a library function call whether or not there is an error,
> provided the use of errno is not documented in the description of the
^^^^^^^^^^^^^^^^^
> function in this International Standard.''
Errno may be set in case of error with not documented errno. Thats how I
read it, but I may miss something.
> Still, my major point was that "0x" sequences are falsely rejected as
It clearly should be rejected with EINVAL in case base == 16,
because 0 alone is not valid HEX sequence and no valid sequence found at
this point. I am not sure about other bases.
> conversion errors, and that strings consisting solely of a plus or
> minus sign should not throw an error either, as I read the C standard.
+- may produce EINVAL, as POSIX says.
In general please don't forget that strtol(), atol() etc. supposed to
parse user input and _detect_ syntax errors, it is their purpose. If they
not do it or do it in half, each program forced to use its own parser
instead.
--
http://ache.pp.ru/
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