# Extra Clang Tools 21.1.6 documentation

## clang-tidy - bugprone-incorrect-enable-shared-from-this

# bugprone-incorrect-enable-shared-from-this

Detect classes or structs that do not publicly inherit from `std::enable_shared_from_this`, because unintended behavior will otherwise occur when calling `shared_from_this`.

Consider the following code:

    #include <memory>

    // private inheritance
    class BadExample : std::enable_shared_from_this<BadExample> {

    // ``shared_from_this``` unintended behaviour
    // `libstdc++` implementation returns uninitialized ``weak_ptr``
        public:
        BadExample* foo() { return shared_from_this().get(); }
        void bar() { return; }
    };

    void using_not_public() {
        auto bad_example = std::make_shared<BadExample>();
        auto* b_ex = bad_example->foo();
        b_ex->bar();
    }

Using libstdc++ implementation, `shared_from_this` will throw `std::bad_weak_ptr`. When `using_not_public()` is called, this code will crash without exception handling.