C Sharp Programming Language Program Execution Code Libraries

The Microsoft C# compiler does not compile to object code which can be executed directly by the target computer. Instead, it is compiled to an intermediate representation. This form consists of metadata and instructions based upon a stack-based virtual machine. All .NET language compilers (which includes Visual Basic .NET, Managed C++, Delphi 8.Net as well as C#) compile to this intermediary code called Common Intermediate Language (CIL). To the casual observer the resulting program looks like a normal WindowsImage use policy. Microsoft Windows is a range of commercial operating environments for personal computers. The range was first introduced by Microsoft in 1985 and eventually has come to dominate the world personal computer market. All recent versions of executable and has an ".exe" extension just like a normal application (code librariesIn computer science, a library is a collection of subprograms used to develop software. Libraries are distinguished from executables in that they are not independent programs; rather, they are "helper" code that provides services to some other independent have the standard ".dll" extension). This is because the executable loader in Windows XP recognises the CIL executable and passes control to the .NET virtual machine. On older operating systems, the CIL executable has a native bootstrapperBootstrapping alludes to a German legend about a man who was able to fly by pulling himself up by his bootstraps. In computers, this term refers to any process where a simple system activates a more complicated system. It is the problem of starting a cert that runs the .NET virtual machine on that assembly.

When the program is executed, the .NET CLR ( Common Language RuntimeIn computing, Common Language Runtime (CLR) is a runtime environment enabling the exact same code called Common Intermediate Language to run on various computers such as Windows PCs, Unix machines and Macintoshes. Microsoft's. NET implementation of the st) compiles the intermediate code into binary code as it is run— just-in-time compilation (JIT). The resulting binary code is stored temporarily (in a memory cache), so if the program uses that portion of code again, the cached version is used. However this is only in effect during the runtime of the program. If a .NET application is run again, this compilation process is done again. The performance of a .NET program can be improved by precompiling the intermediate code to native code using a native code generator utility, but the .NET framework must still be installed for execution.

In addition to compiling intermediate code at runtime, the CLR provides other services. Security mechanisms are built into the CLR so that programs from a low trust source can still be run, with an attempt to limit their permissions. Remoting allows a program to execute code on a different computer over a network. Because code from all .NET languages is compiled to the same intermediate language CIL, code written in different .NET languages can interoperate with no loss in performance.

2 Code libraries

The .NET Framework is a classIn object-oriented programming, a class consists of encapsulated instance variables and subprograms, the methods mentioned below. A Class describes the rules by which objects behave; these objects are referred to as " instances" of that class. A class spe library which can be used from a .NET language to perform tasks from simple data representation and string manipulation to generating dynamic web pages (ASP .NET), XML parsing and reflection. The code is organised into a set of namespaces which group together classes with a similar function, e.g. System.Drawing for graphics, System.Collections for data structures and System.Windows.Forms for the Windows Forms system.

A further level of organisation is provided by the concept of an assembly. An assembly can be a single file or multiple files linked together (through al.exe) which may contain many namespaces and objects. Programs needing classes to perform a particular function might reference assemblies such as System.Drawing.dll and System.Windows.Forms.dll as well as the core library (known as mscorlib.dll in Microsoft's implementation).

3 Example

using System; namespace Example { public sealed class HelloWorld { string myString; public string Value { get { return myString; } set { if (value == null) { throw new ArgumentNullException(); } else { myString = value; } } } public HelloWorld() { myString = "Hello, world!"; } public override String ToString() { return myString; } public static void Main() { HelloWorld myHelloWorld = new HelloWorld(); Console.WriteLine(myHelloWorld.ToString()); Console.WriteLine(myHelloWorld.Value); Console.WriteLine(myHelloWorld); myHelloWorld.Value = "Blah."; Console.WriteLine(myHelloWorld.ToString()); Console.WriteLine(myHelloWorld.Value); Console.WriteLine(myHelloWorld); } //Output is: //Hello, world! //Hello, world! //Hello, world! //Blah. //Blah. //Blah. } }

4 Standardization

Microsoft has submitted C# to the ECMA for formal standardization. In December 2001, ECMA released ECMA-334 C# Language Specification. C# became an ISO standard in 2003 (ISO/IEC 23270). There are independent implementations being worked on, including:

Mono, Ximian's open source .NET implementation
dotGNU & Portable.NET from the Free Software Foundation

More recently, Microsoft has announced plans to add support for generics (similar to C++ templates), partial types and some other new features. Those additions were already proposed for ECMA/ISO standardization.

5 Politics

Many of Microsoft’s products and initiatives generate political attention, and C# is no exception. Due to C#’s close relationship with a commercial institution, political discussions continue regarding the legitimacy of C# standardization, its Java similarities, its future as a general-purpose language, and other various debates. Some security experts express skepticism as to the efficacy of the CLR's security mechanisms, and criticise their complexity.

Unlike proprietary languages such as Visual Basic or Java, Microsoft chose to open C# up to the standardization process. However, Microsoft is still a primary force driving changes and innovation in the language. Additionally, Microsoft has made it clear that C#, as well as the other .NET languages, is an important part of its software strategy for both internal use and external consumption. Microsoft takes an active role in marketing the language as part of its overall business strategy.

6 See also

F# programming language
c Programming Language, Extension to C#
Nemerle programming language
Mono, an open source implementation of C# and .NET
Polyphonic C#
Comparison of C Sharp to Java
Common Language Runtime

7 External links

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1 Program execution