code 39 barcode generator vb.net D. Garbage Collection in Visual Basic .NET

Printing Code 128 Code Set A in Visual Basic .NET D. Garbage Collection

Appendix D. Garbage Collection
Encoding Code 128A In VB.NET
Using Barcode generator for .NET Control to generate, create Code128 image in Visual Studio .NET applications.
www.OnBarcode.com
Recognizing Code-128 In Visual Basic .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
In normal operation, the GC will attempt a collection if there is insufficient memory in the heap to make a new object allocation. The generational approach allows the GC to attempt to satisfy an allocation request by reclaiming memory from the areas of the heap that are most likely to yield a return. Given the assumption that newly allocated objects tend to be short lived, it's likely that a memory requirement can be satisfied by the references in generation 0. If the request cannot be satisfied, the GC can elect to move on to older generations, potentially minimizing the amount of time spent clearing the heap. The GC class provides a method to allow explicit requests for generations to be collected. Calls to the GC.Collect(int) method will cause the indicated generation and all lesser generations to be collected, so a call to collect generation 1 will also cause collection of generation 0. The following GC methods determine which generation an object belongs to:
Generate Barcode In Visual Basic .NET
Using Barcode drawer for .NET Control to generate, create bar code image in .NET applications.
www.OnBarcode.com
Decoding Barcode In Visual Basic .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Int32 GetGeneration(Object obj) Int32 GetGeneration(WeakReference wr)
Code 128C Generation In Visual C#.NET
Using Barcode printer for VS .NET Control to generate, create Code128 image in Visual Studio .NET applications.
www.OnBarcode.com
Paint Code 128 Code Set B In .NET
Using Barcode printer for ASP.NET Control to generate, create Code 128 Code Set B image in ASP.NET applications.
www.OnBarcode.com
The WeakReference class in the second method is discussed in the "Weak References" section later in this appendix.
Generating Code 128B In .NET
Using Barcode generator for Visual Studio .NET Control to generate, create ANSI/AIM Code 128 image in .NET framework applications.
www.OnBarcode.com
Painting Code 128 Code Set C In Visual Basic .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Code128 image in .NET applications.
www.OnBarcode.com
Concurrent Collection
GS1-128 Generator In VB.NET
Using Barcode creator for VS .NET Control to generate, create GTIN - 128 image in .NET applications.
www.OnBarcode.com
Generating QR In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code 2d barcode image in .NET framework applications.
www.OnBarcode.com
By default, the CLR assigns a separate thread for the Garbage Collector (GC), which allows the garbage collector to operate concurrently with application code. Disabling GC concurrency causes memory management to be performed using the same threads that execute the application code. The application will be less responsive, but the performance of GC tasks is greatly increased. Server-side applications typically benefit from disabling GC concurrency. GC concurrency can be controlled by using the .NET application configuration file. For more details about configuration files and an example of disabling GC concurrency, see Appendix C, "Configuring Applications."
Print Linear 1D Barcode In Visual Basic .NET
Using Barcode creation for VS .NET Control to generate, create Linear Barcode image in VS .NET applications.
www.OnBarcode.com
Print C 2 Of 5 In VB.NET
Using Barcode drawer for .NET Control to generate, create Code 2 of 5 image in VS .NET applications.
www.OnBarcode.com
Finalizing and Disposing
Barcode Generation In None
Using Barcode maker for Office Word Control to generate, create bar code image in Office Word applications.
www.OnBarcode.com
Code 128 Code Set A Generator In None
Using Barcode generator for Font Control to generate, create Code 128A image in Font applications.
www.OnBarcode.com
Finalization allows an object to release unmanaged resources it's using before it's collected. The .NET Object class defines the following method signature for this purpose:
Make Bar Code In VS .NET
Using Barcode creator for VS .NET Control to generate, create bar code image in Visual Studio .NET applications.
www.OnBarcode.com
Universal Product Code Version A Printer In Objective-C
Using Barcode creator for iPhone Control to generate, create UPC-A image in iPhone applications.
www.OnBarcode.com
protected override void Finalize();
Code39 Creation In None
Using Barcode generation for Software Control to generate, create Code39 image in Software applications.
www.OnBarcode.com
Making EAN / UCC - 14 In Java
Using Barcode generator for Java Control to generate, create UCC.EAN - 128 image in Java applications.
www.OnBarcode.com
During a collection run, the GC places all unreferenced objects in a finalize queue. This queue is then scanned, and the memory occupied by classes that don't define a Finalize method is released. Objects that do define a Finalize method are placed on the freachable (pronounced F-Reachable) queue. A dedicated thread responsible for calling Finalize methods sleeps when no objects are in the freachable queue. When objects are added to the queue, the thread is awakened and calls the Finalize method.
EAN / UCC - 13 Decoder In C#.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Drawing Data Matrix ECC200 In None
Using Barcode generation for Word Control to generate, create Data Matrix 2d barcode image in Word applications.
www.OnBarcode.com
Appendix D. Garbage Collection
Caution
A dedicated thread calls the Finalize method. Code in the Finalize method can't make assumptions about the state of the thread. For example, local Thread variables won't be available.
Destructors
While the .NET Framework defines the Finalize method, C# doesn't allow classes to override it. Instead, classes that need to clean up resources before collection must implement a destructor. Here's a simple example of a class that defines a destructor:
public class Destructor { public Destructor() { Console.WriteLine("Instantiated"); } ~Destructor() { Console.WriteLine("Destructor called"); } }
The destructor is marked in boldface and takes the form of a constructor with a tilde (~) prepended; destructors take no arguments and return no value. The destructor is implicitly translated to the following code:
protected override void Finalize() { try { Console.WriteLine("Destructor called"); } finally { base.Finalize(); } }
For the following reasons, it's advisable to avoid destructors when designing classes:
Objects with a destructor get promoted to older generations, increasing the pressure on memory allocation and preventing the memory held by the object from being released immediately. Generations are discussed in the "Controlling the Garbage Collector" section earlier in this appendix. Calling a destructor on an object takes time. Forcing the GC to call the destructors for a large number of objects can affect performance. The garbage collector doesn't guarantee when a destructor will be called; objects will hold resources until the method is called, which can put pressure on system memory. A destructor might not be called when an application exits. To allow a process to terminate quickly, destructors aren't called on unreachable objects, and objects that are used by background threads or were created during the termination phase won't be finalized.
Copyright © OnBarcode.com . All rights reserved.