Boost logo

Boost :

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-08-30 16:05:08

----- Original Message -----
From: <scleary_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Thursday, August 30, 2001 4:16 PM
Subject: [boost] RE: Pool question

> > Since pool does not know the type of object that is being allocated, I
> > presume this means that it always uses the maximal alignment
> > for each chunk?
> No. It uses certain properties to guarantee alignment, and to attempt
> minimal alignment (though it will never get smaller than the alignment for
> "void *"). The most important two properties are:
> . "new char[N]" is properly aligned for any object of size N or smaller
> . arrays do not have padding (though the objects in the array may have
> padding)
> Check out the "Guaranteeing Alignment" page of the Boost.Pool docs for
> info. I know it's not very readable; you might want to skip the
> quasi-formal-proof stuff down to where it says "A Look at the Memory
> The splitting up of the block is based on the two properties above.
> > I am allocating an array of objects with an initial reference count. Is
> > there a solution in Boost.Pool for allocating these with minimum
> permissible
> > padding? I don't see one.
> I'm not sure where your "reference count" is going

At the front, which is what I meant by "initial". Specifically:

| count | padding? | elt1 | elt2...

> (so I'm going to ignore
> it here), but Boost.Pool does support allocation of arrays -- check out
> end of the "Guaranteeing Alignment" page to see how. These arrays contain
> no more padding than ordinary arrays would.

I'll look at the docs some more, but if you have answers to the above, they
would be very much appreciated.

Thanks again,

Boost list run by bdawes at, gregod at, cpdaniel at, john at