RE: Pool question

From: scleary_at_[hidden]
Date: 2001-08-30 15:16:49

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

        -Steve