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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::*.
Although function pointers in C and C++ can be implemented as simple addresses, so that typically sizeof(Fx)==sizeof(void *), member pointers in C++ are sometimes implemented as "fat pointers", typically two or three times the size of a simple function pointer, in order to deal with virtual methods and virtual inheritance [citation needed].
Smart pointers typically keep track of the memory they point to, and may also be used to manage other resources, such as network connections and file handles. Smart pointers were first popularized in the programming language C++ during the first half of the 1990s as rebuttal to criticisms of C++'s lack of automatic garbage collection. [1] [2]
In the C++ programming language, auto_ptr is an obsolete smart pointer class template that was available in previous versions of the C++ standard library (declared in the <memory> header file), which provides some basic RAII features for C++ raw pointers. It has been replaced by the unique_ptr class.
Among more structured solutions, a popular technique to avoid dangling pointers in C++ is to use smart pointers. A smart pointer typically uses reference counting to reclaim objects. Some other techniques include the tombstones method and the locks-and-keys method. [3]
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]
In C and C++, constructs such as pointer type conversion and union — C++ adds reference type conversion and reinterpret_cast to this list — are provided in order to permit many kinds of type punning, although some kinds are not actually supported by the standard language.
In C++, while the NULL macro was inherited from C, the integer literal for zero has been traditionally preferred to represent a null pointer constant. [9] However, C++11 introduced the explicit null pointer constant nullptr and type nullptr_t to be used instead, providing a type safe null pointer.