I sometime regret that we have to resort to long
object{_class}_dynamic_cast() calls instead of having a shorter and
more readable macros available, similar to the one recommended by
GObject (https://developer.gnome.org/gobject/stable/gtype-conventions.html).Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> --- include/qom/object.h | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/include/qom/object.h b/include/qom/object.h index f0b0bf39cc..c16e0bc91e 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -101,24 +101,31 @@ typedef struct InterfaceInfo InterfaceInfo; * </programlisting> * </example> * - * Every type has an #ObjectClass associated with it. #ObjectClass derivatives - * are instantiated dynamically but there is only ever one instance for any - * given type. The #ObjectClass typically holds a table of function pointers - * for the virtual methods implemented by this type. + * Every type has an #ObjectClass associated with it. #ObjectClass + * derivatives are instantiated dynamically but there is only ever one + * instance for any given type. The #ObjectClass typically holds a + * table of function pointers for the virtual methods implemented by + * this type. You can cast an #ObjectClass to a subclass (or + * base-class) type using object_class_dynamic_cast(). * - * Using object_new(), a new #Object derivative will be instantiated. You can - * cast an #Object to a subclass (or base-class) type using - * object_dynamic_cast(). You typically want to define macro wrappers around - * OBJECT_CHECK() and OBJECT_CLASS_CHECK() to make it easier to convert to a - * specific type: + * Using object_new(), a new #Object derivative will be instantiated. + * You can cast an #Object to a subclass (or base-class) type using + * object_dynamic_cast(). + * + * You typically want to define macro wrappers to make it easier to + * handle casting: * * <example> * <title>Typecasting macros</title> * <programlisting> * #define MY_DEVICE_GET_CLASS(obj) \ * OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE) + * #define IS_MY_DEVICE_CLASS(klass) \ + * object_class_dynamic_cast(OBJECT_CLASS(klass), TYPE_MY_DEVICE) * #define MY_DEVICE_CLASS(klass) \ * OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE) + * #define IS_MY_DEVICE(obj) \ + * object_dynamic_cast(OBJECT(obj), TYPE_MY_DEVICE) * #define MY_DEVICE(obj) \ * OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE) * </programlisting> -- 2.19.0
