IL code, CLR, CTS, CLS & JIT

IL/MSIL/CIL- IL code is a CPU independent partially compiled code. It’s partially compiled because we do not know in what kind of environment .Net code will run and on runtime IL Code will compile to machine code using the environmental properties (CPU, OS, machine configuration etc). ILDASM- this i

IL/MSIL/CIL- IL code is a CPU independent partially compiled code. It’s partially compiled because we do not know in what kind of environment .Net code will run and on runtime IL Code will compile to machine code using the environmental properties (CPU, OS, machine configuration etc).

ILDASM- this is tool provided by visual studio to view IL code. To run ILDASM we have to select option “Visual Studio Command Prompt” from “Visual Studio Tools” and type ildasm. It will open the ildasm tool where we can open any exe/dll.ildasm tool read the assembly by reflection and it is showing us various properties, methods which our assembly has. Here we can see IL code of any method/property by clicking on that

CLR- CLR is the heart of the .Net framework and it does 4 primary important things-

1. Garbage collection

2. CAS (Code Access Security)

3. CV (Code Verification)

4. IL to Native translation.

CTS- CTS ensure that data types defined in two different languages get compiled to a common data type. This is useful because there may be situations when we want code in one language to be called in other language.

we can see practical demonstration of CTS by creating same application in C# and VB.Net and then compare the IL code of both application. Here the datatype of both IL code is same.

CLS- CLS is a subset of CTS. CLS is a set of rules or guidelines. When any programming language adheres to these set of rules it can be consumed by any .Net language.CTS

JIT-JIT compiles the IL code to Machine code just before execution and then saves this transaction in memory.

CTS

CTS stands for Common Type System. It defines the rules which Common Language Runtime follows when declaring, using, and managing types. The common type system performs the following functions:

1.     It enables cross-language integration, type safety, and high-performance code execution.

2.    It provides an object-oriented model for implementation of many programming languages.

3.    It defines rules that every language must follow which runs under .NET framework. It ensures that objects written in different .NET Languages like C#, VB.NET, F# etc. can interact with each other.

CLS

CLS stands for Common Language Specification and it is a subset of CTS. It defines a set of rules and restrictions that every language must follow which runs under .NET framework. The languages which follows these set of rules are said to be CLS Compliant. In simple words, CLS enables cross-language integration.

For example, one rule is that you cannot use multiple inheritance within .NET Framework. As you know C++ supports multiple inheritance but; when you will try to use that C++ code within C#, it is not possible because C# doesn’t supports multiple inheritance.

One another rule is that you cannot have members with same name with case difference only i.e. you cannot have add() and Add() methods. This easily works in C# because it is case-sensitive but when you will try to use that C# code in VB.NET, it is not possible because VB.NET is not case-sensitive.

Why CTS is Called Common Type System?

In .NET, every Data Type is internally represented by a class or structure. All the classes and structures related to Data Types are collectively known as CTS. As you know every language provides its own keywords for Data Types but internally all the languages which run under .NET framework use the classes and structures available in CTS.

For example, C# has int Data Type and VB.Net has Integer Data Type. Hence a variable declared as int in C# or Integer in vb.net, finally after compilation, use the same structure Int32 from CTS.

All the structures and classes available in CTS are common for all .NET Languages and purpose of these is to support language independence in .NET. Hence it is called CTS.

What do you think?

I hope, you have enjoyed the article about CTS and CLS. I would like to have feedback from my blog readers. Your valuable feedback, question, or comments about this article are always welcome.