[boost] [intrusive_ptr] atomic ref counting?

From: Eric Niebler (eric_at_[hidden])
Date: 2006-04-14 14:56:37

I'm thinking about replacing some uses of shared_ptr with intrusive_ptr, 
but I've got questions. One of the nice things about shared_ptr is the 
lock-free thread-safe ref counting. I want my intrusive_ptr to have the 
same safety and efficiency, but I don't see how to get it. I see 
$boost_root/detail/atomic_count.hpp, but shared_ptr doesn't use it. Why 
not? And why is it in detail/? Should I not consider using it?

Taking in the bigger picture, intrusive_ptr requires people to write 
their own add_ref and release functions, most of which will probably end 
up using ++ and -- on a plain integer. This is totally broken in 
multi-threaded applications, right? Isn't it dangerous to not provide 
complementary utilities for correctly managing reference counts? It 
seems to me intrusive_ptr is impossible to use safely and portably. What 
have I missed?

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com