Programming C# 3.0, 5th Edition

Pointers

Until now, you've seen no code using C-/C++-style pointers. Only here, in the final paragraphs of the final pages of the book, does this topic arise, even though pointers are central to the C family of languages. In C#, pointers are relegated to unusual and advanced programming; typically, they are used only with P/Invoke.

C# supports the usual C pointer operators, listed in Table 23-1.

Table 23-1. C# pointer operators

Operator	Meaning
&	The address-of operator returns a pointer to the address of a value
*	The dereference operator returns the value at the address of a pointer
->	The member access operator is used to access the members of a type

The use of pointers is almost never required, and is nearly always discouraged. When you do use pointers, you must mark your code with the C# unsafe modifier. The code is marked unsafe because you can manipulate memory locations directly with pointers. This is a feat that is otherwise impossible within a C# program. In unsafe code, you can directly access memory, perform conversions between pointers and integral types, take the address of variables, and so forth. In exchange, you give up garbage collection and protection against uninitialized variables, dangling pointers, and accessing memory beyond the bounds of an array. In essence, unsafe code creates an island of C++ code within your otherwise safe C# application, and your code will not work in partial-trust scenarios.

As an example of when this might be useful, read a file to the console ...