ck VS libdill

Maybe I'm missing something, but x is not volatile and the compiler is free to assume that it is not modified concurrently outside the bounds of C's memory model. Compilers can and do hoist out loop invariants, and https://github.com/concurrencykit/ck/commit/b54ae5c4ace9b94442bbb46858449069f566d269 seems like an example of compilers doing what you say they don't. What am I missing?

Recommend checking out http://concurrencykit.org instead.

If you're interested in how other approaches work, or how one achieves concurrency on shared mutable state without mutual exclusion, would recommend checking out concurrency kit.

There are plenty of practical solutions to the safe memory reclamation problem in C. The language just doesn't force one on you.

From epoch-based reclamation (https://github.com/concurrencykit/ck/blob/master/include/ck_..., especially with the multiplexing extension to Fraser's classic scheme), to quiescence schemes (https://liburcu.org/), or hazard pointers (https://github.com/facebook/folly/blob/master/folly/synchron..., or https://pvk.ca/Blog/2020/07/07/flatter-wait-free-hazard-poin...)... or even simple using a type-stable (https://www.usenix.org/legacy/publications/library/proceedin...) memory allocator.

In my experience, it's easier to write code that is resilient to hiccups in C than in Java. Solving SMR with GC only offers something close to lock-freedom when you can guarantee global GC pauses are short enough... and common techniques to bound pauses, like explicitly managed freelists land you back in the same problem space as C.

ck - Concurrency primitives, safe memory reclamation mechanisms and non-blocking data structures. BSD-2-Clause

Indeed they do, https://github.com/concurrencykit/ck

libmill (https://github.com/sustrik/libmill) and libdill (https://github.com/sustrik/libdill) should be similar and probably mentioned.

As far as I understand the differences between CspChan and libmill might be that libmill also implements lightweight tasks (coroutines) and everything that goes with it (IO multiplexing, async timers, etc), while CspChan uses OS threads?

I saw this in 2017. Unfortunately, not much activity now. https://github.com/sustrik/libdill/commits/master

Might be fun to play with, but I wouldn't rely on it. Generally, better off with libuv for existing projects or Rust for greener fields where lifetimes are checked and safe concurrency is much easier.