pointerlike

Pointerlike is a term used in programming to describe values that behave similarly to pointers: they reference a memory location and allow indirect access to the object stored there. A pointerlike value may be a raw address, a language-level reference, or a higher-level handle that encapsulates a reference and its access rules. The key idea is indirection: the value itself is not the object, but a means to reach it.

Examples span multiple languages and abstractions. In C and C++, raw pointers are explicit memory addresses; many languages also provide reference or handle types that act pointerlike without exposing raw addresses, such as Rust’s Box, Rc, and Arc, C++ smart pointers like unique_ptr and shared_ptr, Go’s pointer values, and typical language references in Java and C#. Some languages distinguish safe pointerlike forms (non-nullable references) from unsafe ones (raw pointers).

Pointerlike objects typically incur indirection costs and have ownership or lifetime constraints. They may support dereferencing, and some allow pointer arithmetic or offsetting. Their safety guarantees vary: languages with automatic memory management or borrow checking impose strict rules to prevent hazards such as null dereferences, use-after-free, or data races; unsafe modes expose more direct pointer manipulation but require careful handling.

Uses include implementing dynamic data structures (linked lists, trees), passing large or polymorphic data without copying, and enabling resource management and shared ownership. Pointerlike types are central to abstractions such as smart pointers, iterators, and interface dispatch.

Design considerations: pointerlike semantics affect performance, aliasing, and lifetimes. Good design in a language with pointerlike types balances flexibility with safety, often by providing safe abstractions (references, smart pointers) and explicit unsafe or explicit ownership APIs for low-level programming.