stduniqueptr

std::unique_ptr is a smart pointer in the C++ standard library that provides exclusive ownership of a dynamically allocated object. It is defined in the memory header and is part of the RAII pattern, ensuring that the owned object is automatically deleted when the unique_ptr goes out of scope.

Key characteristics include that std::unique_ptr is non-copyable but movable, meaning ownership can be transferred with std::move but there can be only one owner at a time. It can hold a null pointer, which represents the absence of an object. By default, it deletes the managed object using delete, or delete[] for array types, when it is destroyed. A custom deleter can be supplied as a second template parameter to control how the resource is released.

Common usage patterns emphasize safe construction and ownership transfer. The recommended way to create a unique_ptr is via std::make_unique (introduced in C++14), which provides exception safety and avoids manual new calls. A unique_ptr supports access to the managed object through operator* and operator->, and it exposes methods such as get() to obtain the raw pointer, release() to relinquish ownership without deleting, reset() to replace the managed object, and swap() to exchange contents with another pointer.

There is a specialization std::unique_ptr<T[]> for dynamic arrays, which uses delete[] and provides array-style access via operator[]. The deleter can be customized to manage resources other than memory, such as file descriptors or custom allocations.

Compared with std::shared_ptr, std::unique_ptr enforces unique ownership and does not use reference counting, making it lighter-weight and often preferable for single-ownership scenarios. It is a fundamental tool in modern C++ for safe, automatic resource management.