If I implement the mutex as you suggest -- by using the native semaphore directly, with no separate counter -- the running time of "testBenaphore" increases from 375 ms to 3 seconds on my Windows PC.

As mentioned in the article, most mutex implementations already use this trick. So you can just use std::mutex, and things are fine.

In the past, though, runtime environments weren't so well-developed, so there definitely [was a point](http://www.haiku-os.org/legacy-docs/benewsletter/Issue1-26.h...).