Returning a static cast to a pointer doesn't return a pointer C-CodePudding

In an "Entity" class, there is a function that takes in a component typename as an argument, and should return a pointer to that component, if found in the component array. Instead it just returns a copy of the component, not a pointer, despite doing this:

return static_cast<T*>(ptr)

Here is the relevant code:

ECS.h (only the necessary code).

inline ComponentTypeId getUniqueComponentID() {
    static ComponentTypeId lastID = 0u;
    return lastID  ;
}

template <typename T> inline ComponentTypeId getComponentTypeID() noexcept {
    static_assert(std::is_base_of<Component, T>::value, "Failed at getComponentTypeID/static_assert() --> ECS/ECS.h");
    static const ComponentTypeId typeID = getUniqueComponentID();
    return typeID;
}

// Base "Component" class
class Component {
    // Code
};

// Base "Entity" class
class Entity {
    private:
        ComponentArray compArr;
        ComponentBitset compBitset;
        std::vector<std::unique_ptr<Component>> components;

        bool active = true;

    public:
        Entity() {}
        virtual ~Entity() {}

        template<typename T> bool hasComponent() const {
            // Returns the bitset (bool value)
            return compBitset[getComponentTypeID<T>()];
        }

        template<typename T> T& getComponent() const {
            // Returns pointer to component
            return *static_cast<T*>(compArr[getComponentTypeID<T>()]);
        }

        void update() {
            // Goes through all the components (for this entity) calls their update method
            for(auto &c : components) c->update();
        }

        void draw() {
            // Goes through all the components (for this entity) calls their draw method
            for(auto &c : components) c->draw();
        }

        inline bool isActive() {return active;}
        void destroy() {active = false;}
};

CodePudding user response：

Turns out I was returning a reference instead of a pointer in the getComponent() function.

template<typename T> T& getComponent() const {
    // Returns pointer to component
    return *static_cast<T*>(compArr[getComponentTypeID<T>()]);
}

// Needs to be
template<typename T> T* getComponent() const {
    // Returns pointer to component
    return static_cast<T*>(compArr[getComponentTypeID<T>()]);
}