[defrost]

Sadly I can't ask the author anymore, I suspect this was a least feature possible stripped down port of a more battle tested cross platform library that dated to before the times of modern multi multi multi core chips.

Concurrency issues existed in the days of yore .. but they arose in different ways with different timings.

It's an odd bit of code archeology recalling a concept ( mmap ring buffers ) from decades past and then hunting to find the best remaining example - much of LibH was 'clean' rewrites of code from the authors past work.