Comment by mgaunard

10 hours ago

that isn't a mutex, that's delegating work asynchronously and delegating something else to run when it is complete (the implicitly defined continuation through coroutines).

In systems programming parlance, a mutex is a resource which can be acquired and released, acquired exactly once, and blocks on acquire if already acquired.

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mgaunard

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gpderetta  9 hours ago

Do a CPS transform of your typical std::mutex critical section and you'll find they are exactly the same.

  • mgaunard  9 hours ago

    They're not, the interactions with the memory model are different, as are the guarantees.

    CPS shouldn't be able to deadlock for example?

    • gpderetta  9 hours ago

      CPS can trivially deadlock for all meaningful definitions of deadlock.

      Would you consider this a mutex?

         async_mutex mux;

   co_await mux.lock();
   /* critical section */
   co_await mux.unlock();

      What about: my_mutex mux;

         {
      std::lock_guard _{mux};
      /* critical section */
   }

      where the code runs in a user space fiber.

      Would you consider boost synchronized a mutex?

      Don't confuse the semantics with the implementation details (yes async/await leaks implementation details).