CODEWITHSUNDEEP
concurrencytheorysemaphore
sdcvvc
sdcvvc

Reputation: 25644

Are semaphores "complete"?

Can every imaginable synchronization problem be solved with judicious use of semaphores? What about weak semaphores?

Upvotes: 0

Views: 357

Answers (2)

sdcvvc
sdcvvc

Reputation: 25644

Agerwala argues that appropiately extended semaphores are complete. This doesn't answer all my questions, but is on right track. David Seiler has a point too.

Upvotes: 0

David Seiler
David Seiler

Reputation: 9705

No. Just for example, it's impossible for a system that uses only semaphores for synchronization to provide wait-free guarantees, or even progress guarantees, in the face of third-party code (e.g. a plugin). A perverse or poorly-written section of code can deny access to a semaphore-guarded section of code to everyone forever.

Upvotes: 3

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