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Some objects in gtkmm are obtained from a shared store. Consequently you cannot instantiate them yourself. Instead they return a RefPtr which behaves much like an ordinary pointer in that members can be reached with the usual object_ptr->member
notation. Unlike most other smart pointers, RefPtr doesn't support dereferencing through * object_ptr
.
Reference counting means that a shared reference count is incremented each time a RefPtr is copied, and decremented each time a RefPtr is destroyed, for instance when it leaves its scope. When the reference count reaches zero, the contained object is deleted, meaning you don't need to remember to delete the object.
RefPtr<> can store any class that has reference() and unreference() methods. In gtkmm, that is anything derived from Glib::ObjectBase, such as Gdk::Pixmap.
See the "Memory Management" section in the "Programming with gtkmm" book for further information.
Public Member Functions | |
RefPtr () | |
Default constructor. | |
~RefPtr () | |
Destructor - decrements reference count. | |
RefPtr (T_CppObject* pCppObject) | |
For use only by the ::create() methods. | |
RefPtr (const RefPtr<T_CppObject>& src) | |
Copy constructor. | |
template <class T_CastFrom> | RefPtr (const RefPtr<T_CastFrom>& src) |
Copy constructor (from different, but castable type). | |
void | swap (RefPtr<T_CppObject>& other) |
Swap the contents of two RefPtr<>. | |
RefPtr<T_CppObject>& | operator= (const RefPtr<T_CppObject>& src) |
Copy from another RefPtr:. | |
RefPtr<T_CppObject>& | operator= (T_CppObject* pCppObject) |
For use only by the ::create() methods. | |
template <class T_CastFrom> RefPtr<T_CppObject>& | operator= (const RefPtr<T_CastFrom>& src) |
Copy from different, but castable type). | |
bool | operator== (const RefPtr<T_CppObject>& src) const |
Tests whether the RefPtr<> point to the same underlying instance. | |
bool | operator!= (const RefPtr<T_CppObject>& src) const |
See operator==(). | |
T_CppObject* | operator-> () const |
Dereferencing. | |
operator bool () const | |
Test whether the RefPtr<> points to any underlying instance. | |
bool | is_null () const |
Test whether the RefPtr<> points to any underlying instance. | |
void | clear () |
Set underlying instance to 0, decrementing reference count of existing instance appropriately. | |
Static Public Member Functions | |
template <class T_CastFrom> RefPtr<T_CppObject> | cast_dynamic (const RefPtr<T_CastFrom>& src) |
Dynamic cast to derived class. | |
template <class T_CastFrom> RefPtr<T_CppObject> | cast_static (const RefPtr<T_CastFrom>& src) |
Static cast to derived class. | |
Related Functions | |
(Note that these are not member functions.) | |
void | swap (RefPtr<T_CppObject>& lhs, RefPtr<T_CppObject>& rhs) |
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Default constructor. Afterwards is_null() will return true and use of -> will cause a segmentation fault. |
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Destructor - decrements reference count.
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For use only by the ::create() methods.
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Copy constructor. This increments the shared reference count. |
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Copy constructor (from different, but castable type). Increments the reference count. |
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Dynamic cast to derived class. The RefPtr can't be cast with the usual notation so instead you can use ptr_derived = RefPtr<Derived>::cast_dynamic(ptr_base); |
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Static cast to derived class. Like the dynamic cast; the notation is ptr_derived = RefPtr<Derived>::cast_static(ptr_base); |
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Set underlying instance to 0, decrementing reference count of existing instance appropriately.
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Test whether the RefPtr<> points to any underlying instance.
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Test whether the RefPtr<> points to any underlying instance. Mimics usage of ordinary pointers: if (ptr)
do_something();
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See operator==().
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Dereferencing.
Use the methods of the underlying instance like so: |
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Copy from different, but castable type). Increments the reference count. |
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For use only by the ::create() methods.
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Copy from another RefPtr:.
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Tests whether the RefPtr<> point to the same underlying instance.
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Swap the contents of two RefPtr<>. This method swaps the internal pointers to T_CppObject. This can be done safely without involving a reference/unreference cycle and is therefore highly efficient. |
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