A semaphore is used to restrict the variety of threads which have entry to a shared useful resource on the similar time. In different phrases, a Semaphore means that you can implement non-exclusive locking and therefore restrict concurrency. You would possibly consider a Semaphore as a non-exclusive type of a Mutex. In .NET, we use the System.Threading.Semaphore class to work with semaphores.
Create a mutex in C#
Let’s create a mutex object in .NET. Word that we use the WaitOne methodology on an occasion of the Mutex class to lock a useful resource and the ReleaseMutex methodology to unlock it.
Mutex mutexObject = new Mutex(false, "Demo"); attempt { if (!mutexObject.WaitOne(TimeSpan.FromSeconds(10), false)) { Console.WriteLine("Quitting for now as one other occasion is in execution..."); return; } } lastly { mutexObject.ReleaseMutex(); } Allow us to now implement a real-life code instance that makes use of a mutex to synchronize entry to a shared useful resource. The next code itemizing demonstrates how you should use a Mutex object in C# to synchronize entry to a crucial part that writes knowledge to a textual content file.
public static class FileLogger { non-public const string fileName = @"D:ProjectsMyLog.txt"; public static void WriteLog(string textual content) { utilizing var mutex = new Mutex(initiallyOwned: false, "Internationallog"); attempt { mutex.WaitOne(1000); File.AppendAllText(fileName, textual content); } catch (AbandonedMutexException) { mutex.ReleaseMutex(); mutex.WaitOne(1000); File.AppendAllText(fileName, textual content); } lastly { mutex.ReleaseMutex(); } } } Within the FileLogger class proven above, an try is made to amass a mutex by blocking the present thread for 1000 milliseconds. If the mutex is acquired, the textual content handed to the AppendAllText methodology as a parameter is written to a textual content file. The lastly block then releases the mutex by making a name to the ReleaseMutex methodology.
