Date: Fri, 9 Aug 2013 02:10:02 GMT From: Garrett Cooper <yaneurabeya@gmail.com> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/181153: sscanf doesn't skip whitespace properly Message-ID: <201308090210.r792A21J042982@freefall.freebsd.org>
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The following reply was made to PR kern/181153; it has been noted by GNATS.
From: Garrett Cooper <yaneurabeya@gmail.com>
To: Andrey Chernov <ache@freebsd.org>
Cc: "FreeBSD-gnats-submit@FreeBSD.org" <freebsd-gnats-submit@freebsd.org>
Subject: Re: bin/181153: sscanf doesn't skip whitespace properly
Date: Thu, 8 Aug 2013 19:03:10 -0700
On Thu, Aug 8, 2013 at 6:24 PM, Andrey Chernov <ache@freebsd.org> wrote:
> On 09.08.2013 4:23, Garrett Cooper wrote:
>> ATF_TC_BODY(sscanf_whitespace, tc)
>> {
>> const char str[] = "\f\n\r\t\v%z";
>> char c;
>>
>> /* set of "white space" symbols from isspace(3) */
>> c = 0;
>> (void)sscanf(str, "%%%c", &c);
>> ATF_REQUIRE(c == 'z');
>> }
>
> I doubt this exampe should skip whitespace. POSIX says:
> "A directive that is an ordinary character shall be executed as follows:
> the next byte shall be read from the input and compared with the byte
> that comprises the directive; if the comparison shows that they are not
> equivalent, the directive shall fail, and the differing and subsequent
> bytes shall remain unread."
> %% is the ordinary % character and no isspace(3) skipping mentioned in
> this explanation.
What about this line [*]?
"
A directive composed of one or more white-space characters is executed
by reading input until no more valid input can be read, or up to the
first byte which is not a white-space character which remains unread.
"
I think this is what the NetBSD test developer was shooting for originally.
FWIW I did print out the value previously and it was (char)0, or '\0'.
Thanks!
* http://pubs.opengroup.org/onlinepubs/7908799/xsh/fscanf.html
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