Improved instructions and fill line sticker help eliminate confusion and overfilling the water.Improved insulation on all water lines eliminate condensation at the control box and water leakage when directions are followed.The New digital timer facilitates the use of the system per the doctors direction.Panel mount right angle coupling makes a mistake-proof watertight seal.Cooler lid is hinged and snaps in place, keeping it properly sealed.High-flow, dry and quick disconnect couplings allow for freedom of movement if required.Easy to reuse simply add ice and water to the cooler.Universal Therapy Bladder can be applied to any part of the body that needs to be targeted cooling therapy.Specifically designed for post-surgery, where serious pain relief is required.Returns the ID of the new timer.Why Choose Active Ice Therapy System With 9 Quart Cooler? Semaphore(unsigned int count = 0) : m_count(count) ) The only helper class needed is a semaphore, which can be implemented in portable C++11 with a mutex, a condition_variable and a counter. Extraneous notifications to wake up the thread have no side effects, since the thread wakes up, checks for work, recalculates the new wait time and goes back to waiting. The thread wakes up when something has changed (e,g: Timer added/cancelled, or expired), and checks for work (e.g: execute handlers for expired timers). I kept thinking off the thread-to-thread communication as “ work to be done“, and thus the obvious choice there was to have a command queue.Īfter a moment of clarity, I changed my mindset from “ work to be done” to “ something has changed“, and a cleaner solution formed: What was sabotaging my efforts was that I was in the wrong mindset. Maybe it just got that bad in small increments as I was focusing on the wrong problems. To be honest, in hindsight that first pass was quite bad. Ever had that feeling of “ Surely there must be a cleaner way to do this” ? Sure enough, as I started to write this post to share the code, I’ve spotted another bug. To add insult to injury, those two queues were locked independently. There was a queue for the timers, then communication with the worker thread was done with another queue where I would pass commands such as “recalculate wait time”, or “execute this timer right now”, or “shutdown”. My first pass at this was convoluted to say the least. If performance is a problem, profile it, then think as hard as you need to get it right and fast. Sure, performance is good, but first get it right. Personally, I think it’s a bad sign if to verify correctness of your multithreaded code you have to think too hard. Now, if you throw in a couple more threads adding or cancelling timers, things might get confusing. Worker thread needs to rethink the waiting time, since timer B should be executed before A.Main thread adds a timer B with expiry time 1 second.Worker thread detects there is a timer in the queue, and starts a wait based on that timer expiry time.
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