reinterpretcast

reinterpret_cast is a C++ cast operator used for low-level reinterpretation of a value’s representation. It performs a bitwise reinterpretation of the underlying bits to produce an object of a different type, rather than applying a conventional conversion. The operator is intended for scenarios where you need to treat a value as a different type without changing its bit pattern.

The operator can cast between pointer types, between a pointer and an integer type large enough to hold a pointer, and between function pointer types. Its syntax is reinterpret_cast<NewType>(expression). Common examples include reinterpreting a raw pointer as a pointer to another type, converting a pointer to a void* or back, or turning an integer value into a pointer or a pointer into an integer. It can also convert between unrelated function pointer types. Because reinterpret_cast performs a low-level reinterpretation, it does not perform safety checks or value-based conversions.

Safety and portability are important considerations. reinterpret_cast is implementation-defined and can lead to undefined behavior if used incorrectly, especially when dereferencing the resulting pointer or when the targeted type has a different object representation or alignment. It should be used sparingly and only when other, safer casts (such as static_cast, dynamic_cast, or const_cast) are inappropriate. For tasks like accessing raw memory, many programmers prefer memcpy or std::bit_cast (in C++20) to avoid undefined behavior and improve portability.

Common use cases include low-level systems programming, interfacing with hardware, or working with serialization formats where exact byte representation must be preserved. In typical object-oriented design, reinterpret_cast is rarely needed, and safer casting or higher-level abstractions are usually preferred.