C++ is considering a new primitive called synchronic which is similar to futex but has a few different tradeoffs, would work better on some hardware, and would be portable. There's a sample implementation with data, and @ogiroux is working on a new paper with an updated API.

It would be good to understand why synchronic isn't used JavaScript's shared memory:

• Maybe synchronic itself would benefit from corrections.
• Maybe it is a good fit, but is misunderstood (see demonstration below).
• Will synchronic usage in C++17 (or whenever it's standardized) be mappable to JavaScript's primitives?