[Bug libc/12701] scanf accepts non-matching input

["bugdal at aerifal dot cx" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=12701

Rich Felker <bugdal at aerifal dot cx> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |

--- Comment #2 from Rich Felker <bugdal at aerifal dot cx> 2011-05-02 02:35:40 UTC ---
They are not correctly handled. Please refer to C99, 7.19.6.2, paragraph 9,
which defines an input item as:

"the longest sequence of input characters which does not exceed any speciïed
ïeld width and which is, or is a preïx of, a matching input sequence"

Paragraph 10 then reads:

"If the input item is not a matching sequence, the execution of the directive
fails: this condition is a matching failure."

Clearly in the case of sscanf("0xz", "%x%c", &x, &c), the first "input item" is
"0x", and it is not a matching sequence for the %x conversion (see the
specification of strtoul, in terms of which scanf %x is specified), so the
result must be a matching failure.

If you're going to wrongly mark this bug as "RESOLVED", at least mark it
"WONTFIX" rather than "INVALID" and acknowledge that it's a bug that you're
unwilling to fix, and that glibc is intentionally non-conformant in this
matter.

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