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In computer science, a smart pointer is an abstract data type that simulates a pointer while providing added features, such as automatic memory management or bounds checking. Such features are intended to reduce bugs caused by the misuse of pointers, while retaining efficiency. 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]
Pointer misuse can be a major source of bugs. Smart pointers prevent most situations of memory leaks by making the memory deallocation automatic. More generally, they make object destruction automatic: an object controlled by a smart pointer is automatically destroyed (finalized and then deallocated) when the last (or only) owner of an object is destroyed, for example because the owner is a local variable, and execution leaves the variable's scope. Smart pointers also eliminate dangling pointers by postponing destruction until an object is no longer in use.
If a language supports automatic garbage collection (for example, Java or C#), then smart pointers are unneeded for reclaiming and safety aspects of memory management, yet are useful for other purposes, such as cache data structure residence management and resource management of objects such as file handles or network sockets.
Several types of smart pointers exist. Some work with reference counting, others by assigning ownership of an object to one pointer.