dereferences

Dereferencing is the operation of accessing the value stored at a particular memory location or the object referred to by a reference or pointer. In low-level languages, dereferencing a pointer means following the pointer to read or modify the object it points to. The dereference operation is often implemented with a dedicated operator, such as the asterisk (*) in C and C++, yielding the value at the pointer as well as enabling writes to that location.

In languages with automatic memory management and references, such as Java or C#, dereferencing is typically implicit: a reference variable denotes an object, and accessing its fields or methods constitutes a dereference. Some languages also support explicit pointer types alongside authorities that manage memory safety; for example, Go uses the & operator to take addresses and the * operator to dereference pointers when needed.

Rust models dereferencing through the * operator and a deref trait that allows automatic coercions between types. References to values (e.g., &T) can be dereferenced to access the underlying value, with deref coercions enabling method calls or field access to feel natural across reference types. Box<T>, Rc<T>, and other smart pointer types provide managed indirection, with additional rules around ownership, borrowing, and lifetime.

Safety considerations are central to dereferencing: dereferencing a null or invalid pointer can cause crashes or undefined behavior in languages like C and C++. Modern languages mitigate this with null checks, optional types, or automatic memory safety features. Correct use of dereferencing is essential for proper memory access, performance, and program correctness.