Working with Characters and Strings(Chapter 3 of Windows Via C/C++)

　　Because kernel object handles are process-relative, performing these tasks is difficult. However, Microsoft had several good reasons for designing the handles to be process-relative. The most important reason was robustness. If kernel object handles were systemwide values, one process could easily obtain the handle to an object that another process was using and wreak havoc on that process. Another reason for process-relative handles is security. Kernel objects are protected with security, and a process must request permission to manipulate an object before attempting to manipulate it. The creator of the object can prevent an unauthorized user from touching the object simply by denying access to it.

　　There are three different mechanisms that allow processes to share kernel objects: using object handle inheritance, naming objects, and duplicating object handles.