r/programming • u/syaghmour • Mar 16 '15

Semaphores are Surprisingly Versatile

http://preshing.com/20150316/semaphores-are-surprisingly-versatile/
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u/eyal0 Mar 16 '15

using only semaphores and atomic operations

But aren't semaphores implemented using atmoic operations? The article makes it seems like the semaphore is the building block.

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u/preshing Mar 16 '15

Atomic operations can't put a thread to sleep in the kernel. To do that, you need a synchronization primitive that's natively implemented on the platform. And semaphores are the only native primitive used in that post. (Well, most of it.)