C# Language Specification - Willy .Net

Chapter 18 Structsstruct Point{int x, y;public Point(int x, int y) {this.x = x;this.y = y;}}Given the above declaration, the statementsPoint p1 = new Point();Point p2 = new Point(0, 0);both create a Point with x and y initialized to zero. end example]A struct instance constructor is not permitted to include a constructor initializer of the form base(…).The this variable of a struct instance constructor corresponds to an out parameter of the struct type, andsimilar to an out parameter, this must be definitely assigned (§12.3) at every location where theconstructor returns. [Example: Consider the instance constructor implementation below:struct Point{int x, y;public int X {set { x = value; }}public int Y {set { y = value; }}public Point(int x, int y) {X = x; // error, this is not yet definitely assignedY = y; // error, this is not yet definitely assigned}}No instance member function (including the set accessors for the properties X and Y) can be called until allfields of the struct being constructed have been definitely assigned. Note, however, that if Point were aclass instead of a struct, the instance constructor implementation would be permitted.end example]18.3.9 DestructorsA struct is not permitted to declare a destructor.18.3.10 Static constructorsStatic constructors for structs follow most of the same rules as for classes. The execution of a staticconstructor for a struct is triggered by the first of the following events to occur within an applicationdomain:• An instance member of the struct is referenced.• A static member of the struct is referenced.• An explicitly declared constructor of the struct is called.[Note: The creation of default values (§18.3.4) of struct types does not trigger the static constructor. (Anexample of this is the initial value of elements in an array.) end note]18.4 Struct examplesThis whole clause is informative.271