What is Unmanaged Code and Unmanaged Code Execution? and what is CCW and RCW?

Unmanaged Code:

• The code that has written before development of .Net for which MSIL is not available is not executed by CLR directly, rather CLR redirects the code to OS for Execution, which is known as Unmanaged code.
• The code which has developed outside .Net framework is known as Unmanaged code.
• Applications that do not run under the control of the CLR are said to be unmanaged, and certain languages such as C++ can be used to write such applications, which, for example, access low - level functions of the operating system. Background compatibility with code of VB, ASP and COM are examples of unmanaged code.

Unmanaged Code Execution:

• The code execution process is known as Unmaged Code Exection.
• CLR will not provide any facilities and features of .Net to Unmanaged Code Execution like Language Interoperability, Automatic Management, Common Data Type System, Exception Handling Mechanism, Code Access Security etc.

Unmanged code executed with helper of wrapper classes.

Wrapper classes are two types:

1. CCW (COM Callable Wrapper)
2. RCW (Runtime Callable Wrapper)

COM callable wrapper unmanaged code execution

Runtime Callable Wrapper unmanaged code execution