Common Language Runtime

Common Language Runtime

The CLR stands for Common Language Runtime is an Execution Environment. It works as a layer between Operating Systems and the applications written in .Net languages that conforms to the Common Language Specification (CLS).

The common language runtime (CLR) is the core runtime engine for executing applications in the .NET Framework. The CLR allows an instance of a class written in one language to call a method of the class written in another language. At the base level, it is the infrastructure that executes applications, and allows them to interact with the other parts of the Framework. The code which runs under the CLR is called as Managed Code. Programmers need not to worry on managing the memory if the programs are running under the CLR as it provides memory management and thread management. The main function of Common Language Runtime (CLR) is to convert the Managed Code into native code and then execute the Program. It acts as a layer between Operating Systems and the applications written in .Net languages.

Compilers and tools expose the common language runtime's functionality and enable you to write code that benefits from this managed execution environment. Code that you develop with a language compiler that targets the runtime is called managed code; it benefits from features such as cross-language integration, cross-language exception handling, enhanced security, versioning and deployment support, a simplified model for component interaction, and debugging and profiling services.

CLR handles the execution of code and provides useful services for the implementation of the program. In addition to executing code, CLR provides services such as memory management, thread management, security management, code verification, compilation, and other system services.

The main function of Common Language Runtime (CLR) is to convert the Managed Code into native code and then execute the Program. The Managed Code compiled only when it needed, that is it converts the appropriate instructions when each function is called . The Common Language Runtime (CLR) 's just in time (JIT) compilation converts Intermediate Language (MSIL) to native code on demand at application run time.

Functions of the CLR:

Class Loader:

Used to load all classes at run time.

MSIL to Native code compiler:

The Just In Time (JTI) compiler will convert MSIL code into native code.

Code Manager:

It manages the code at run time.

Garbage Collector:

It manages the memory. Collect all unused objects and deallocate them to reduce memory.

Thread Support:

It supports multi-threading of our application.

Exception Handler:

Exception Manager will handle exceptions thrown by application by executing catch block provided by exception, it there is no catch block , it will terminate application.

- Prof. Shardul P. Patil