The unsafe keyword may be used to modify a procedure or define a block of code which uses unsafe code. Code is unsafe if it uses the "address of" (&) or pointer operator (*).

In order for the compiler to compile code containing this keyword, you must use the unsafe option when using the Microsoft C-Sharp Compiler.

class MyClass {
  public static void Main() {
    int x = 2;
    // example of unsafe to modify a code block
    unsafe {
      DoSomething(&x);
    }
  }

  // example of unsafe to modify a procedure
  unsafe static void DoSomething(int *msg) {
    Console.WriteLine(*msg);
  }
}