[ngbronson]

One option for compatibility on non-futex platforms is to write your own futex emulation using striped std::mutex or pthread_mutex_t. The emulated futex API still has the same slow-path-only goodness as a real futex, but is fully portable.

For an example of this technique, check out https://github.com/facebook/folly/blob/master/folly/detail/F... . That code only implements wake and wait, but it would be straightforward to extend it to the other futex operations.