Return a `T*` to indicate a position (only)

Reason

That's what pointers are good for. Returning a T* to transfer ownership is a misuse.

Example

Node* find(Node* t, const string& s)  // find s in a binary tree of Nodes
{
    if (!t || t->name == s) return t;
    if ((auto p = find(t->left, s))) return p;
    if ((auto p = find(t->right, s))) return p;
    return nullptr;
}

If it isn't the nullptr, the pointer returned by find indicates a Node holding s. Importantly, that does not imply a transfer of ownership of the pointed-to object to the caller.

Note

Positions can also be transferred by iterators, indices, and references. A reference is often a superior alternative to a pointer if there is no need to use nullptr or if the object referred to should not change.

Note

Do not return a pointer to something that is not in the caller's scope; see F.43.

See also: discussion of dangling pointer prevention

Enforcement

Only owners should be deleted.

Only owners should be responsible for deletion.

• Flag delete, std::free(), etc. applied to a plain T*.
• Flag new, malloc(), etc. assigned to a plain T*.