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From: Ian Collins <ian-news@hotmail.com>
Newsgroups: comp.lang.c
Subject: Re: Memory corruption on freeing a pointer to pointer
Date: Tue, 27 Aug 2013 09:16:24 +1200
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Xref: csiph.com comp.lang.c:35881

Ike Naar wrote:
> On 2013-08-26, Ian Collins <ian-news@hotmail.com> wrote:
>> James Kuyper wrote:
>>> On 08/26/2013 02:40 AM, Ike Naar wrote:
>>>> On 2013-08-25, Keith Thompson <kst-u@mib.org> wrote:
>>>>> James Kuyper <jameskuyper@verizon.net> writes:
>>>>>> On 08/24/2013 03:05 PM, Sharwan Joram wrote:
>>>>> [...]
>>>>>>>             if ( NULL == parameters[parametercount]){
>>>>>
>>>>> This is what's known as a "Yoda conndition"
>>>>> <http://en.wikipedia.org/wiki/Yoda_Conditions>.  I know that a lot of
>>>>> programmers like them, and for somewhat valid reasons, but personally I
>>>>> find them jarring and unnecessary.  Personally, I'd write that as:
>>>>>
>>>>>       if (parameters[parametercount] == NULL) {
>>>>
>>>> Does it matter? The == operator is symmetric, (X==Y) == (Y==X).
>>>
>>> Yes, it matters - because it's intended to protect against the typo
>>> which replaces == with =, by ensuring that it would cause a constraint
>>> violation. The assignment operator is very definitely not symmetric.
>>
>> The best way to protect against that particular typo is decent unit tests.
>
> Do not overestimate the value of unit tests.
> Let's take, for example, a piece of code that multiplies two
> 32-bit numbers to obtain a 64-bit result.

What has that got to do with this particular typo?

-- 
Ian Collins