c# generating barcode Primitive Thread Synchronization Constructs in .NET framework

Printer QR in .NET framework Primitive Thread Synchronization Constructs

28
Create QR Code 2d Barcode In .NET
Using Barcode generation for ASP.NET Control to generate, create QR image in ASP.NET applications.
www.OnBarcode.com
Print Barcode In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create barcode image in ASP.NET applications.
www.OnBarcode.com
Primitive Thread Synchronization Constructs
Encoding QR Code In Visual C#
Using Barcode creation for .NET framework Control to generate, create QR Code image in Visual Studio .NET applications.
www.OnBarcode.com
Encoding QR Code In .NET
Using Barcode creation for Visual Studio .NET Control to generate, create QR Code image in VS .NET applications.
www.OnBarcode.com
Most people do not like this additional logic . The problem is that these features have a cost associated with them . The Mutex object needs more memory to hold the additional thread ID and recursion count information . And, more importantly, the Mutex code has to maintain this information, which makes the lock slower . If an application needs or wants these additional features, then the application code could have done this itself; the code doesn t have to be built into the Mutex object . For this reason, a lot of people avoid using Mutex objects . Usually a recursive lock is needed when a method takes a lock and then calls another method that also requires the lock, as the following code demonstrates:
Creating Quick Response Code In Visual Basic .NET
Using Barcode generation for VS .NET Control to generate, create QR Code ISO/IEC18004 image in Visual Studio .NET applications.
www.OnBarcode.com
Print QR-Code In .NET
Using Barcode creation for ASP.NET Control to generate, create QR image in ASP.NET applications.
www.OnBarcode.com
internal class SomeClass : IDisposable { private readonly Mutex m_lock = new Mutex(); public void Method1() { m_lock.WaitOne(); // Do whatever... Method2(); // Method2 recursively acquires the lock m_lock.ReleaseMutex(); } public void Method2() { m_lock.WaitOne(); // Do whatever... m_lock.ReleaseMutex(); } public void Dispose() { m_lock.Dispose(); } }
Barcode Encoder In .NET Framework
Using Barcode maker for ASP.NET Control to generate, create bar code image in ASP.NET applications.
www.OnBarcode.com
Make PDF-417 2d Barcode In VS .NET
Using Barcode encoder for ASP.NET Control to generate, create PDF-417 2d barcode image in ASP.NET applications.
www.OnBarcode.com
In the code above, code that uses a SomeClass object could call Method1, which acquires the Mutex, performs some thread-safe operation, and then calls Method2, which also performs some thread-safe operation . Since Mutex objects support recursion, the thread will acquire the lock twice and then release it twice before another thread can own the Mutex . If SomeClass has used an AutoResetEvent instead of a Mutex, then the thread would block when it called Method2 s WaitOne method . If you need a recursive lock, then you could create one easily by using an AutoResetEvent:
Create EAN 128 In VS .NET
Using Barcode creation for ASP.NET Control to generate, create UCC.EAN - 128 image in ASP.NET applications.
www.OnBarcode.com
Matrix 2D Barcode Creator In .NET
Using Barcode maker for ASP.NET Control to generate, create 2D Barcode image in ASP.NET applications.
www.OnBarcode.com
internal sealed class RecursiveAutoResetEvent : IDisposable { private AutoResetEvent m_lock = new AutoResetEvent(true); private Int32 m_owningThreadId = 0; private Int32 m_recursionCount = 0; public void Enter() { // Obtain the calling thread's unique Int32 ID Int32 currentThreadId = Thread.CurrentThread.ManagedThreadId; // If the calling thread owns the lock, increment the recursion count if (m_owningThreadId == currentThreadId) { m_recursionCount++; return; }
Making UPC A In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create UPC-A image in ASP.NET applications.
www.OnBarcode.com
Leitcode Generator In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create Leitcode image in ASP.NET applications.
www.OnBarcode.com
Part V
Encoding Code 128 Code Set B In VS .NET
Using Barcode drawer for .NET Control to generate, create Code 128A image in VS .NET applications.
www.OnBarcode.com
Barcode Creator In None
Using Barcode creator for Font Control to generate, create barcode image in Font applications.
www.OnBarcode.com
Threading
Bar Code Generator In Java
Using Barcode drawer for BIRT Control to generate, create barcode image in BIRT reports applications.
www.OnBarcode.com
Encoding Barcode In VS .NET
Using Barcode printer for Reporting Service Control to generate, create bar code image in Reporting Service applications.
www.OnBarcode.com
// The calling thread doesn't own the lock, wait for it m_lock.WaitOne(); // The calling now owns the lock, initialize the owning thread ID & recursion count m_owningThreadId = currentThreadId; m_recursionCount--;
Drawing Code 3 Of 9 In Objective-C
Using Barcode drawer for iPad Control to generate, create Code39 image in iPad applications.
www.OnBarcode.com
Reading ECC200 In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
} public void Leave() { // If the calling thread doesn't own the lock, we have an error if (m_owningThreadId != Thread.CurrentThread.ManagedThreadId) throw new InvalidOperationException(); // Subtract 1 from the recursion count if (--m_recursionCount == 0) { // If the recursion count is 0, then no thread owns the lock m_owningThreadId = 0; m_lock.Set(); // Wake up 1 waiting thread (if any) } } public void Dispose() { m_lock.Dispose(); } }
Generating GS1 128 In Java
Using Barcode generation for Eclipse BIRT Control to generate, create UCC-128 image in Eclipse BIRT applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Encoder In None
Using Barcode generator for Microsoft Excel Control to generate, create QR Code image in Office Excel applications.
www.OnBarcode.com
While the behavior of the RecursiveAutoResetEvent class is identical to that of the Mutex class, a RecursiveAutoResetEvent object will have far superior performance when a thread tries to acquire the lock recursively because all the code that is required to track thread ownership and recursion is now in managed code . A thread has to transition into the Windows kernel only when first acquiring the AutoResetEvent or when finally relinquishing it to another thread .
Calling a Method When a Single Kernel Construct Becomes Available
Having a thread block indefinitely waiting for a kernel object to become available is wasteful of the thread s memory resources . Therefore, the thread pool offers a way to invoke a method of yours when a kernel object becomes available by using the System.Threading. ThreadPool class s static RegisterWaitForSingleObject method . There are several overloads of this method, but they are all very similar . Here is the prototype for one of the more commonly used overloads:
public static RegisteredWaitHandle RegisterWaitForSingleObject( WaitHandle waitObject, WaitOrTimerCallback callback, Object state, Int32 millisecondsTimeoutInterval, Boolean executeOnlyOnce);
28
Primitive Thread Synchronization Constructs
When you call this method, the waitObject argument identifies the kernel object that you want the thread pool to wait for . Since this parameter is of the abstract base class WaitHandle, you can specify any class derived from this base class . Specifically, you can pass a reference to a Semaphore, Mutex, AutoResetEvent, or ManualResetEvent object . The second parameter, callback, identifies the method that you want the thread pool thread to call . The callback method that you write must match the System.Threading. WaitOrTimerCallback delegate, which is defined as follows:
public delegate void WaitOrTimerCallback(Object state, Boolean timedOut);
Copyright © OnBarcode.com . All rights reserved.