C#•2y ago

❔ Cross Thread synchronization of locks

In over my head, I am trying to use a lock to pause some code on one thread, and i want to release (Monitor.Exit()) from another thread. How do i synchronise this?

71 Replies

Unknown User•2y ago

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Boggo•2y ago

im not aware of how to synchronise because i am exiting from another thread that the lock was entered on, its throwing up an error

Unknown User•2y ago

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Boggo•2y ago

Boggo•2y ago

so this runs on a thread the cw will be taken out, its just for testing purposes then i call _halter.Exit(); from another Thread

Unknown User•2y ago

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Boggo•2y ago

queue

Unknown User•2y ago

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Boggo•2y ago

the idea of the locks was that it wasnt gonna infinitely run a while true loop

Unknown User•2y ago

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Boggo•2y ago

how does channel work?

Unknown User•2y ago

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MODiX•2y ago

see $channel

Unknown User•2y ago

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MODiX•2y ago

Opinion: first article looks better as an introduction than the devblog one, but but should still be read in that order https://ndportmann.com/system-threading-channels https://devblogs.microsoft.com/dotnet/an-introduction-to-system-threading-channels https://www.stevejgordon.co.uk/an-introduction-to-system-threading-channels Video: https://docs.microsoft.com/en-us/shows/on-net/working-with-channels-in-net

Exploring System.Threading.Channels

A blog about software engineering and applied cryptography.

.NET Blog

An Introduction to System.Threading.Channels - .NET Blog

“Producer/consumer” problems are everywhere, in all facets of our lives. A line cook at a fast food restaurant, slicing tomatoes that are handed off to another cook to assemble a burger, which is handed off to a register worker to fulfill your order,

Unknown User•2y ago

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Boggo•2y ago

i would probably agree. however

Unknown User•2y ago

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Boggo•2y ago

in a hypothetical situatuation where i needed to use a lock and queue since this is for school xD

Unknown User•2y ago

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Boggo•2y ago

is it possible like how im trying?

Unknown User•2y ago

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Boggo•2y ago

i should probably read up a little on locks not sure i understand this

Unknown User•2y ago

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Boggo•2y ago

 private static void StoreMessages()
        {
            while (true)
            {
                if (_messagesToStore.Count == 0)
                {
                    lock (_halter)
                    {
                    }
                }

                var msg = _messagesToStore.Dequeue();
                Console.WriteLine("Message Uploaded");
                _db.AddNewTextMessage(msg);
                
            }
            
        }

 private static void StoreMessages()
        {
            while (true)
            {
                if (_messagesToStore.Count == 0)
                {
                    lock (_halter)
                    {
                    }
                }

                var msg = _messagesToStore.Dequeue();
                Console.WriteLine("Message Uploaded");
                _db.AddNewTextMessage(msg);
                
            }
            
        }

i have changed now trying to edit myself

private static void StoreMessages()
        {
            while (true)
            {
                Monitor.Enter(_halter);
                try
                {
                    if (_messagesToStore.Count == 0)
                    {
                        Monitor.Wait(_halter);
                    }

                    var msg = _messagesToStore.Dequeue();
                    _db.AddNewTextMessage(msg);
                }
                finally
                {
                    Monitor.Exit(_halter);
                }
            }
            
        }

private static void StoreMessages()
        {
            while (true)
            {
                Monitor.Enter(_halter);
                try
                {
                    if (_messagesToStore.Count == 0)
                    {
                        Monitor.Wait(_halter);
                    }

                    var msg = _messagesToStore.Dequeue();
                    _db.AddNewTextMessage(msg);
                }
                finally
                {
                    Monitor.Exit(_halter);
                }
            }
            
        }

heres original it holds it until i exit it from the other thread

Unknown User•2y ago

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Boggo•2y ago

someone else mentioned reset events too, i had a look but im pressed on time for this so looking for something simple as possible

Unknown User•2y ago

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Boggo•2y ago

no clue, its my coursework its due friday. Teacher suddenly said he wants it done haha

Unknown User•2y ago

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Boggo•2y ago

i need to finish the solution. Then complete testing and evaluation for my school, the computer science course requires we complete a full project Analysis, design, implementation, testing and evaluation

Unknown User•2y ago

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Boggo•2y ago

not sure, but i would be using months to measure not years

Unknown User•2y ago

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Boggo•2y ago

i have played about with it for maybe 1.5 years, but for the first year i was playing with strings and arrays

Unknown User•2y ago

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Boggo•2y ago

ok this is manual?

Unknown User•2y ago

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Boggo•2y ago

yes this one, so i use either or, or do i need both

Boggo•2y ago

https://learn.microsoft.com/en-us/dotnet/api/system.threading.autoresetevent?view=net-7.0

AutoResetEvent Class (System.Threading)

Represents a thread synchronization event that, when signaled, resets automatically after releasing a single waiting thread. This class cannot be inherited.

Boggo•2y ago

i am reading here

Unknown User•2y ago

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Boggo•2y ago

so theres not a huge difference a bit like having a using statement rather that calling .Close() ?

Unknown User•2y ago

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Boggo•2y ago

oh, forget my question then haha

Unknown User•2y ago

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Boggo•2y ago

so i need manual i believe

Unknown User•2y ago

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Boggo•2y ago

i may have 10+ threads all adding to queue

Unknown User•2y ago

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Boggo•2y ago

ok i see. I will look at channel again, hopefully i get my head around it pretty quick

Unknown User•2y ago

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Boggo•2y ago

https://tenor.com/view/spongebob-scared-scary-sad-gif-26439591

Tenor

Unknown User•2y ago

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Boggo•2y ago

ok sure, ill try plug it in and see what happens. But not gonna spend too long if it doesnt go well

Unknown User•2y ago

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Boggo•2y ago

yes, will try this first

Unknown User•2y ago

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Boggo•2y ago

i know a little about this i used to use await Task.Run(() => SomeAsyncTask)

Unknown User•2y ago

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Boggo•2y ago

i know haha it was very bodge job code

Unknown User•2y ago

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Boggo•2y ago

but i said, i am still new and learning. This is my first proper project

Unknown User•2y ago

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Boggo•2y ago

oke doke appreciate your time fingers crossed all goes well So i was being dumb i fixed using Locks and monitor i just never synchronised the two threads by entering on both only entered on one thread where i waited from pule i need to enter then pulse then exit i just pulsed

Boggo•2y ago

https://tenor.com/view/my-bad-confused-oops-jennifer-lawrence-gif-16942960

Tenor

Unknown User•2y ago

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Boggo•2y ago

im aware, my bad

Unknown User•2y ago

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Mayor McCheese•2y ago

Channel ftw

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Cross Thread synchronization of locks