Concurrency primitives, safe memory reclamation mechanisms and non-blocking (including lock-free) data structures designed to aid in the research, design and implementation of high performance concurrent systems developed in C99+.
Will address, thanks. Commit message (1537c8091da102c649b7335d0de7d4005c510ac4) has some more details on lock / unlock, not relevant to most platforms.
I noticed that the following fences are lacking documentation:
ck_pr_fence_lock()
ck_pr_fence_unlock()
ck_pr_fence_acqrel()
The latter has intuitive semantics, but the *lock variants don't.