Re: [VOTE]strn(case)cmp supporting a negative length as its third paramter

From: Date: Sun, 14 Aug 2011 21:37:59 +0000
Subject: Re: [VOTE]strn(case)cmp supporting a negative length as its third paramter
References: 1 2 3 4 5 6 7 8 9 10 11 12  Groups: php.internals 
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On 08/14/2011 02:03 PM, Stas Malyshev wrote:
> Hi!
> 
> On 8/14/11 11:40 AM, Rasmus Lerdorf wrote:
>> My main issue with changing strncmp/strncasecmp is that these are
>> currently exact mappings of the underlying libc functions. For people
> 
> And why should anybody care? 99% of people using PHP never used a libc
> function and can hardly tell libc from gcc. If we can extend this
> function with useful functionality, nobody cares about what libc does.
> 
>> For example, I could imagine people writing code along these lines:
>>
>> $len = strlen($user_data) - strlen($suffix);
>> if(!strncmp($user_data, $string, $len)) {
>>     // do something
>> }
> 
> Warning doesn't fix the bug - and unless you're in 0.0001% of the
> population that actually reads the logs daily and checks every message
> there it would be little to help you. We should have more useful
> functions, not more warnings. Warning won't make this code to work.

I agree, however this change would potentially change the return value
of the function. Before it would warn and not match. Even if you never
saw the warning, at least length -1 would not give you a match. Now if
the user data happens to end with the right character we now have a
string match which is not at all what the code was written to do.

-Rasmus


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