UnManaged code in .net

.Code for which there is no MSIL executed after the language compile compilation is not executed by the CLR directly rather the CLR will collect all the required resources and redirectly the code to as for execution which is known as unmanaged code And the code execution process is known as unmanaged code execution
For unmanaged code exe CLR does not provide any features of facilities like common
1. data type system
2. Automatic memory management
3. JIT compilation
4. Exception handling mechanism etc

.net source code(Managed code)-->LC-->MSIL-->CLR(unmanagedcode)-->Nativecode-->Code executed