Re: bzr commit into mysql-5.1-bugteam branch (Alexey.Kopytov:3514) Bug#56709

[Alexey Kopytov]

On 01.10.10 12:04, Tor Didriksen wrote:
> On Thu, Sep 30, 2010 at 2:36 PM, Sergei Golubchik<serg@stripped>  wrote:
>
>> Hi, Davi!
>>
>> On Sep 30, Davi Arnaut wrote:
>>> On 9/30/10 8:33 AM, Tor Didriksen wrote:
>>>> On Fri, Sep 24, 2010 at 11:20 AM, Alexey Kopytov
>>>>>>
>>>>>>   I personally think of bzero() as a convenient alias for the
> most
>>>>>>   commonly used form of memset(). In other words, even if
> bzero()
>>>>>>   did not exist, it should have been created. And we actually do
>>>>>>   something like that in m_string.h:
>>>>>>
>>>>>>   #if !defined(bzero)&&   !defined(HAVE_BZERO)
>>>>>>   # define bzero(A,B)             memset((A),0,(B))
>>>>>>   #endif
>>>>
>>>> Time for another update of the style guide I guess,
>>>> we shouldn't be recommending functions which are deprecated.
>>>
>>> Definitely. bzero is a officially deprecated function and we never
>>> actually use it because it depends on some BSD defines that we never
>>> set.
>>
>> So, Kaamos is right after all :)
>>
>> Coding style does not recommend a deprecated function, furthermore this
>> deprecated function was never used. bzero() is just a convenience macro,
>> and should be fine as such. The fact that libc has deprecated a function
>> does not apply to MySQL internal macro that happen to have the same
>> name :)
>>
>
> no ??
>
> #if !defined(bzero)&&  !defined(HAVE_BZERO)
> # define bzero(A,B)             memset((A),0,(B))
> #endif
>
> configure/cmake will define HAVE_BZERO
> and we end up calling the deprecated function in the C library
>
> -- didrik
>

Yes, we do use bzero(), at least on Linux, Solaris and Mac OS X, since 
we include both string.h (which defines bzero() only when __USE_BSD is 
defined) and strings.h (which seems to define bzero() on complementary 
to __USE_BSD conditions).

But then again, 
http://www.opengroup.org/onlinepubs/000095399/functions/bzero.html :

"For maximum portability, it is recommended to replace the function call 
to bzero() as follows:

#define bzero(b,len) (memset((b), '\0', (len)), (void) 0)
"

Which is what we do in m_string.h when bzero() is unavailable. "For 
maximum portability". Does that mean we comply with POSIX? Or, why 
should we care about the legacy status of bzero() at all?

/Alexey.