Re: [boost] [lockfree] tagged_ptr as a separate library

Subject: Re: [boost] [lockfree] tagged_ptr as a separate library
From: Tim Blechmann (tim_at_[hidden])
Date: 2012-03-30 09:21:15

> >> Wouldn't it make sense to move it into a separate library entirely? It
> >> would possibly get more exposure and cross-platform ports. The technique
> >> itself also requires some extra documentation. And it might find it's
> >> way into a release earlier than lock-free itself.
> > 
> > for now i prefer to keep it an implementation detail. but maybe it can be
> > exposed to the public API in future. how now i'd like to wait until there
> > are some std::atomic implementation which can actually compile the
> > tagged_ptr. i hope boost.lockfree will be in 1.50, still waiting for
> > boost.atomic, though
> Isn't tagged_ptr also useful even when it is not used atomically?

i've personally not seen any use case for a tagged pointer except for 
prevention of the ABA problem. especially the pointer-compression is mainly to 
pack pointer and tag into a 64bit memory region, which is mainly required for 
systems without 128bit compare-and-swap ...