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The void pointer, or void*, is supported in ANSI C and C++ as a generic pointer type. A pointer to void can store the address of any object (not function), [a] and, in C, is implicitly converted to any other object pointer type on assignment, but it must be explicitly cast if dereferenced.
A custom interface, anything derived from IUnknown, provides early bound access via a pointer to a virtual method table that contains a list of pointers to the functions that implement the functions declared in the interface, in the order they are declared. An in-process invocation overhead is, therefore, comparable to a C++ virtual method call.
When an object is created, a pointer to this table, called the virtual table pointer, vpointer or VPTR, is added as a hidden member of this object. As such, the compiler must also generate "hidden" code in the constructors of each class to initialize a new object's virtual table pointer to the address of its class's virtual method table.
In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
Type sensitivity is a variant of object sensitivity where the allocation site of the receiver object is replaced by the class/type containing the method containing the allocation site of the receiver object. [13] This results in strictly fewer contexts than would be used in an object-sensitive analysis, which generally means better performance.
An example for which a conservative garbage collector would be needed is the C language, which allows typed (non-void) pointers to be type cast into untyped (void) pointers, and vice versa. A related issue concerns internal pointers, or pointers to fields within an object. If the semantics of a language allow internal pointers, then there may ...
Non-static member functions (instance methods) have an implicit parameter (the this pointer) which is the pointer to the object it is operating on, so the type of the object must be included as part of the type of the function pointer. The method is then used on an object of that class by using one of the "pointer-to-member" operators: .* or ...
Objects that are shared but not owned can be accessed via a reference, raw pointer, or iterator (a conceptual generalisation of pointers). However, by the same token, C++ provides native ways for users to opt-into such functionality: C++11 provides reference counted smart pointers, via the std::shared_ptr class, enabling automatic shared memory ...