[SmartPtr] intrusive_ref_counter CounterPolicyT requirements API?

From: Billy (billy.donahue_at_[hidden])
Date: 2020-12-04 16:11:14

Hi Boost,

We're considering implementing our own atomic ref count for
`intrusive_ref_count` [*]. A question came up. Is the `CounterPolicyT`
template parameter a stable extension hook, or are users expected to
strictly stick to the two provided policies of `thread_unsafe_counter` and
`thread_safe_counter`?  I can see that under the hood, these policy structs
are trivially simple and we can just do it, but the question is really
about whether the lack of documentation implies that it's a private boost
detail.

From
https://www.boost.org/doc/libs/1_74_0/libs/smart_ptr/doc/html/smart_ptr.html#intrusive_ref_counter

"The second parameter is a policy that defines the nature of the reference
counter. The library provides two such policies: thread_unsafe_counter and
thread_safe_counter."

Thanks for your time,
    Billy Donahue

[*] Incidentally we want to increment with memory order relaxed instead of
acq_rel.

-- 
ǝnɥɐuop ʎllıq