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From: Richard <rgrdev_@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: pass by address
Date: Mon, 05 May 2014 12:00:25 +0200
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"Bill Cunningham" <nospam@nspam.invalid> writes:

> "Keith Thompson" <kst-u@mib.org> wrote in message 
> news:lnr44aj596.fsf@nuthaus.mib.org...
>> Tonton Th <tth@nowhere.invalid> writes:
>>> On 2014-05-04, Barry Schwarz <schwarzb@dqel.com> wrote:
>>>>>#include <stdio.h>
>>>>>
>>>>>int main()
>>>>>{
>>>>>    int a = 15;
>>>>>    int *p;
>>>>>    p = &a;
>>>>>    printf("%p\n", &p);
>>>>
>>>> Undefined behavior #1.
>>>>
>>>>>    printf("%p\n", p);
>>>>
>>>> Undefined behavior #2.
>>>>
>>>>>    printf("%d\n", *p);
>>>>>}
>>>
>>>    I don't understand where in the undefined behaviour. Not so usable
>>>    values printed, yes, but &p and p are pointers, so %p can print their
>>>    values, no ?
>>>
>>>    Maybe because p and &p are not 'void *' pointers...
>>
>> That's exactly it.  "%p" requires an argument of type void*, not of any
>> arbitrary pointer type.  In practice, most implementations use the same
>> representation and argument passing convention for all pointer types, so
>> it's likely to work, but for well-defined behavior you need to cast the
>> arguments to void*.
>
>     Well I learned something today new. I'll keep that in mind. What would 
> be the best way to take careof that in your opinion? Cast a (void *). These 
> are the little things that you need to know so when you get into big 
> programs could cause real problems.
>
> Bill
>

lol!

10/10

"when you get into big programs"

Genius!


-- 
"Avoid hyperbole at all costs, its the most destructive argument on
the planet" - Mark McIntyre in comp.lang.c