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Date: Sun, 10 Nov 2002 20:19:35 -0800 (PST)
From: "Randy.Dunlap" <rddunlap@osdl.org>
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To: "Henning P. Schmiedehausen" <hps@intermeta.de>
cc: <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Re: sscanf("-1", "%d", &i) fails, returns 0
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On Sun, 10 Nov 2002, Randy.Dunlap wrote:

| On Sun, 10 Nov 2002, Henning P. Schmiedehausen wrote:
|
| | "Randy.Dunlap" <rddunlap@osdl.org> writes:
| |
| | >+		digit = *str;
| | >+		if (is_sign && digit == '-')
| | >+			digit = *(str + 1);
| |
| | If signed is not allowed and you get a "-", you're in an error case
| | again...
|
| Yes, and a 0 value is returned.
| IOW, asking for an unsigned number (in the format string)
| and getting "-123" does return 0.
|
| What should it do?
| This function can't return -EINPUTERROR or -EILSEQ.
| (since it's after feature-freeze :)
| And the original problem was that a leading '-' sign on a
| signed number (!) caused a return of 0.  At least that is fixed.
|
| So now the problem (?) is that a '-' sign on an unsigned number
| returns 0.  We can always add a big printk() there that
| something is foul.  Other ideas?

It's noteworthy that vsscanf() completely gives up on scanning
the rest of the input data at this point.  E.g.:
	count = sscanf (input, "%x %i %i", &level, &next, &other);
with <input> = "-42 -86 -99" gives up on "-42" and returns 0
(as number of items scanned/converted).

-- 
~Randy

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