Is the vptr at the beginning of an object?

[Ian Collins]

Well, I was hoping to get an answer from someone who has experience and
knowledge across a number of popular compilers. Getting JUST the answer
about gcc would have been "OK", but I didn't even get that. Where better
than a C++ group to ask? While I don't NEED the answer anymore, I am
still curious about it. When I first posted though, I did need the info,
and certainly not dogma.

The question remains unanswered, unless it's in one of the posts I
haven't read yet.

That says a lot about the question! I'm sure most programmers, no
matter how experienced don't know the answer, because they've never
needed to.

 

[DaveB]

Joshua Maurice wrote:

[...]

Again as a practical matter, when I hear people ask questions like
"what offset is the vptr at?", simply answering the question does the
group and the person a disservice.

[...]

True,

Noooo. It's not TRUE at all. He removed the context to suit his agenda.
Think about it again. I don't think you'll buy what he is selling.

Choosing to _only_ provide that additional
information and brushing off the interest in the original question
with "who cares" could legitimately be viewed as rude or patronizing.

I don't need anyone to interpret the standard for me. I have a copy or 2
or 3 of the draft. I used to chat on IRC. The popular opinion is that
when a public room gets too dominating by one person or group, they
should make their own place, because it limits and constrains people. Oh,
it IS awfully convenient though huh. Nuff said.

 

[DaveB]

Excuse me, but I did answer the question.

"Excuse lil ol me", but dude, I asked the question and I still have it so
you have not done that, but I know you're just trying to infalible. Guess
what demigod: you're not a god. You "fucked up", and now "have fucked up
royally". Deal with it. No one has answered my question, you still have
not and this is sad that the thread overall is about you. "Ain't no
fuckng question anymore". Nope. It's all you babe.

The fact that the
correct answer to the question (i.e. the facts) doesn't happen
to please the original poster is a different issue; I can't do
anything about that, since the facts aren't likely to change.

I don't know how to help you. Psychologist? Nope, they are in your
circle. Psychiatrist? Nope, you're not crazy, I hope! Wait, let me
consult my crystal... ah! Of course. The crystal said to me, and surely I
am just the messenger, "the wind is a harsh mistress" and "time...". Does
that message from the crystal make sense to you? I think it means ...
well it doesn't matter what I think it means. I hope it helps! (You off
of your high horse so I can kick your butt! Just kidding.)

[...]

Maybe this question is compiler specific and should be asked
in a compiler specific newsgroup.

It's not that compiler specific, since every compiler I know
does use multiple vptr, and none makes any guarantee with
regards to where the vptrs will be in the object.

Keep hiding JK. I'd say I hope it works out for you in your own ng, but
1. I don't think you'd venture that far and 2. I thought this shit was
over a decade ago. Maybe you should do 2 just to prove that it isn't so??
Aww c'mon, I dare ya.

 

[DaveB]

Peter Remmers wrote:

I saved what I wrote in response, cuz off-the-cuff, I'm not that kind and
don't need or want to be.

 

[DaveB]

You read "who cares" as "You should not care" or even "none of Your
business" ... I read it "I don't care". Latter is closer on common
case ... people usually talk about themselves and not about others. In
any case "who cares" does not mean that "stop reading", since he
further explained why worrying about it has no value.

As for rest of that Jameses answer

I never meant this simple question to be about JK or stumping him. But
apparently, the facts show that he is stupid and can't answer the
simplest of questions, and surely for fear for his life someone should go
to his home and feed him oatmeal so that he can continue to live for all
hope for him would be lost if it were known to anyone that he gave the
wrong answer. I will retract my question to relieve myself of this burden
and hardship that anyone wants to bring upon me. I will not ignore him
though, for I am, of course, now, the C++ DEMIGOD! I wish him the best,
in his retirement.

 

[DaveB]

James Kanze wrote:

[some gibberish]

I am learning to think before I speak. Hey, maybe you should too? Just
kidding. I know I'm "older and playing with the kids in the sandbox".

I had a real question. And now, I mean no offense, so, what I do is send
my posts to "draft", when it is anything political, religious or sexual.
Haha, someone, more than one, told me that a long time ago: don't ever
talk about politics, religion, sex. Surely it was a politician. ... for
to curb thought, is to own.... what? A hundred years ago, there were not
cars. A hundred years later, people DREAM of a world without cars.

 

[DaveB]

That says a lot about the question! I'm sure most programmers, no
matter how experienced don't know the answer, because they've never
needed to.

I posed the question to "programmers"? Is that what you meant? If so, I'm
so sorry. I didn't know.

 

[Krice]

In practice, across most compilers, is the vptr at offset 0 of a class
object? I've found some posts that say GCC puts it at the end, but they
were very old posts and I don't use it now so can't test it.

Look what I found from internets:
http://www.devx.com/tips/Tip/14876

Might just work. I don't know, I don't care.

 

[James Kanze]

[...]

That says a lot about the question! I'm sure most
programmers, no matter how experienced don't know the answer,
because they've never needed to.

Most of the programmers I know do know the correct answer: "it
depends, and it might change with the next release of the
compiler, but it doesn't matter".

 

[DaveB]

Ian Collins wrote:
On 04/ 5/10 06:21 PM, DaveB wrote:

[...]

The question remains unanswered, unless it's in one of the posts I
haven't read yet.

That says a lot about the question! I'm sure most
programmers, no matter how experienced don't know the answer,
because they've never needed to.

Most of the programmers I know do know the correct answer: "it
depends, and it might change with the next release of the
compiler, but it doesn't matter".

My "response" is saved. You have nothing to tell me while you think it is
a secret. There is nothing wrong with you or who you are. You are good.
You come with a label, that I KNOW is not you but your "brand".

I drink too much, duh. Programme against that. It's "my job" to call you
out.