Re: [boost] [proposal]AtomicallyThread-SafeReferenceCountingAlgorithm...

From: Chris Thomasson (cristom_at_[hidden])
Date: 2006-10-22 16:55:45

"Chris Thomasson" <cristom_at_[hidden]> wrote in message 
news:ehgjr6$iru$1_at_sea.gmane.org...
> "Peter Dimov" <pdimov_at_[hidden]> wrote in message 
> news:00e901c6f613$06ed8a00$6607a8c0_at_pdimov2...
>> Chris Thomasson wrote:

[...]

> Are you referring to the case in which a collection was not protected by a 
> mutex? If so, I was basically referring to some sort of lock-free, or 
> mostly lock-free collection. You can use ptr::global in a lock-free 
> collection, it isn't very practical because of the spinlock, but it is 
> compatible. Its was just a simple example to show some of the algorithms 
> flexibility...

To clarify, you can use ptr::global in the anchor structure of a lock-free 
collection. For example:

template<typename T_state>
struct node {
  ptr::global<node> m_next;
  T_state *m_state;
};

// packed structure
template<typename T_node>
struct lflifo_anchor {
  ptr::global<T_node> m_node;
  uintword_t m_aba;
};

typedef lflifo_anchor<node<foo> > my_anchor_foo_t;

my_anchor_foo_t can be modified with DWCAS, because (sizeof(my_anchor_foo_t) 
== (sizeof(void*) * 2)).