C++ Special Member Function Guidelines

The C++ special member functions are:

default constructor

copy constructor

move constructor

destructor

copy assignment

move assignment

They can be either = defaulted, = deleted, not manually written at all, or have a custom implementation.

The majority of classes you write will match one of the four options listed below. When in doubt, do what normal does (rule of zero).

class normal public: normal(); // if it makes sense ~normal() = default;

normal(const normal&) = default; normal(normal&&) = default;

normal& operator=(const normal&) = default; normal& operator=(normal&&) = default; };

class immoveable public: immoveable(); // if it makes sense ~immoveable() = default;

immoveable(const immoveable&) = delete; immoveable& operator=(const immoveable&) = delete;

immoveable(immoveable&&) = delete; immoveable& operator=(immoveable&&) = delete; };

class container public: container() noexcept; ~container() noexcept;

container(const container& other); container(container&& other) noexcept;

container& operator=(const container& other); container& operator=(container&& other) noexcept; };

class resource_handle public: resource_handle() noexcept; ~resource_handle() noexcept;

resource_handle(const resource_handle&) = delete; resource_handle& operator=(const resource_handle&) = delete;

resource_handle(resource_handle&& other) noexcept; resource_handle& operator=(resource_handle&& other) noexcept; };

Shown in italics are the effective compiler-generated implementations of the special members; you can write them yourself to be explicit.

Full rationale and further explanations: Tutorial: When to Write Which Special Member

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