[lttng-dev] [rp] [RFC PATCH urcu] urcu_ref_get: API change: return boolean

[Josh Triplett]

On Thu, Jan 21, 2016 at 04:45:20PM +0000, Mathieu Desnoyers wrote:
> ----- On Jan 19, 2016, at 3:57 PM, Mathieu Desnoyers mathieu.desnoyers at efficios.com wrote:
> 
> > This is a RFC of a follow up patch based on urcu commit 7d7c5d467 "Fix:
> > handle reference count overflow".
> > 
> > Change the urcu_ref_get prototype to return a boolean, which takes the
> > value false if a LONG_MAX overflow would occur (get has not been
> > performed), or true otherwise.
> > 
> > This interface change also introduces a "warn_unused_result" gcc
> > function attribute, which will show warnings if users don't handle the
> > return value.
> > 
> > I'm wondering whether this change is useful enough to justify breaking
> > the API (need to bump the major library version), or if introducing a
> > new "urcu_ref_get_safe()" or such would be a better option ?
> 
> After some thinking, I will go for adding a new urcu_ref_get_safe() API,
> thus not requiring to bump the library major version.

You may want to add a deprecated __attribute__ to the unsafe version in
the header.

- Josh Triplett