Search results
Results from the WOW.Com Content Network
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 C++ pointers to non-static members of a class can be defined. If a class C has a member T a then &C::a is a pointer to the member a of type T C::*. This member can be an object or a function. [16] They can be used on the right-hand side of operators .* and ->* to access the corresponding member.
These are invoked using an object pointer or a this call. They are type safe in that you can only call members of that class (or derivatives) using a pointer of that type. This example also demonstrates the use of a typedef for the pointer to member function added for simplicity. Function pointers to static member functions are done in the ...
In C++, classes can be forward-declared if you only need to use the pointer-to-that-class type (since all object pointers are the same size, and this is what the compiler cares about). This is especially useful inside class definitions, e.g. if a class contains a member that is a pointer (or a reference) to another class.
C++11 introduces the thread_local [3] keyword which can be used in the following cases Namespace level (global) variables; File static variables; Function static variables; Static member variables; Aside from that, various compiler implementations provide specific ways to declare thread-local variables:
The d-pointer pattern is one of the implementations of the opaque pointer. It is commonly used in C++ classes due to its advantages (noted below). A d-pointer is a private data member of the class that points to an instance of a structure. This method allows class declarations to omit private data members, except for the d-pointer itself. [6]
Smart pointers can facilitate intentional programming by expressing, in the type, how the memory of the referent of the pointer will be managed. For example, if a C++ function returns a pointer, there is no way to know whether the caller should delete the memory of the referent when the caller is finished with the information.
Note that, when there is a data member that is a pointer or reference to another object, then it is possible to mutate the object pointed to or referenced only within a non-const method. C++ also provides abstract (as opposed to bitwise) immutability via the mutable keyword, which lets a member variable be changed from within a const method.