Return null structure

Eugene Eugene 1, 9 9 silver badges 21 21 bronze badges. GetOffMyLawn yes because it is the syntax to tell it will return a nullable type — Franck. This all makes sense, I thought I had to create the struct Nullable , but that is built in as System. A struct cannot be nullable. You are simply marking the method in a way that it can return an object of type of the struct OR it will return a null object not typed. Franck Perhaps it's the wording, but your last comment is confusing. Only structs can be used with Nullable.

A struct itself cannot be null i. Yes i see the confusion. I used nullable when i meant null. Sign up or log in Sign up using Google. Sign up using Facebook. A struct X directly depends on a struct Y if X contains an instance field of type Y. Given this definition, the complete set of structs upon which a struct depends is the transitive closure of the directly depends on relationship. Another example.

With classes, it is possible for two variables to reference the same object, and thus possible for operations on one variable to affect the object referenced by the other variable. With structs, the variables each have their own copy of the data except in the case of ref and out parameter variables , and it is not possible for operations on one to affect the other.

Note : If a struct contains a field of reference type then the contents of the object referenced can be altered by other operations. However the value of the field itself, i. The assignment of a to b creates a copy of the value, and b is thus unaffected by the assignment to a. Had Point instead been declared as a class, the output would be because a and b would reference the same object.

All struct types implicitly inherit from the class System. ValueType , which, in turn, inherits from class object. A struct declaration may specify a list of implemented interfaces, but it is not possible for a struct declaration to specify a base class. Struct types are never abstract and are always implicitly sealed.

The abstract and sealed modifiers are therefore not permitted in a struct declaration. Since inheritance isn't supported for structs, the declared accessibility of a struct member cannot be protected or protected internal. Function members in a struct cannot be abstract or virtual, and the override modifier is allowed only to override methods inherited from System. Assignment to a variable of a struct type creates a copy of the value being assigned.

This differs from assignment to a variable of a class type, which copies the reference but not the object identified by the reference. Similar to an assignment, when a struct is passed as a value parameter or returned as the result of a function member, a copy of the struct is created.

A struct may be passed by reference to a function member using a ref or out parameter. This is one of the reasons why the usage of NULL is preferred because it makes it explicit in code that programmer is using null pointer, not integer 0.

This statement is also from C11 clause 7. It means that internal representation of the null pointer could be non-zero bit pattern to convey NULL pointer. Having said so, typically NULL is represented as all bits set to 0 only. Well, usage of sizeof NULL is allowed but the exact size would depend on platform. If the pointer size of a platform is 4 bytes, the output of the above program would be 4.

But if pointer size on a platform is 8 bytes, the output of the above program would be 8. Skip to content. Change Language. Related Articles. That is, if the HasValue property is true , the contents of the Value property is boxed. If the HasValue property of a nullable type is false , the result of a boxing operation is null.

Consequently, if a boxed nullable type is passed to a method that expects an object argument, that method must be prepared to handle the case where the argument is null. Starting with the. NET Framework 4. Previously, this was not supported. Retrieves the hash code of the object returned by the Value property.