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| System.Glib.GObject | | Portability | portable (depends on GHC) | | Stability | provisional | | Maintainer | gtk2hs-users@lists.sourceforge.net |
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| Description |
| The base object type for all glib objects
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| Synopsis |
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| Types
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| newtype GObject |
| Constructors | |  Instances | |
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| class GObjectClass o where |
| | Methods | | | | Instances | |
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| toGObject :: (GObjectClass o, GObjectClass o) => o -> GObject |
| Safe upcast.
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| unsafeCastGObject :: (GObjectClass o, GObjectClass o) => GObject -> o |
| Unchecked downcast.
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| castToGObject :: GObjectClass obj => obj -> obj |
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| Low level binding functions
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| All these functions are internal and are only interesting to people
writing bindings to GObject-style C libraries.
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| objectNew :: GType -> [(String, GValue)] -> IO (Ptr GObject) |
| Construct a new object (should rairly be used directly)
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| objectRef :: GObjectClass obj => Ptr obj -> IO () |
| Increase the reference counter of an object
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| objectUnref :: FinalizerPtr a |
| Decrease the reference counter of an object
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| objectRefSink :: GObjectClass obj => Ptr obj -> IO () |
| Reference and sink an object.
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| makeNewGObject |
| :: GObjectClass obj | | | => (ForeignPtr obj -> obj) | constructor for the Haskell object
| | -> IO (Ptr obj) | action which yields a pointer to the C object
| | -> IO obj | | This function wraps any object that does not derive from Object.
It should be used whenever a function returns a pointer to an existing
GObject (as opposed to a function that constructs a new object).
- The first argument is the contructor of the specific object.
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| constructNewGObject :: GObjectClass obj => (ForeignPtr obj -> obj) -> IO (Ptr obj) -> IO obj |
| This function wraps any object that does not
derive from Object. The object is NOT reference, hence it should be used
when a new object is created. Newly created GObjects have a reference
count of one, hence don't need ref'ing.
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| GType queries
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| isA :: GObjectClass o => o -> GType -> Bool |
| Determine if this is an instance of a particular GTK type
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| Callback support
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| type DestroyNotify = FunPtr (Ptr () -> IO ()) |
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| mkFunPtrDestroyNotify :: FunPtr a -> IO DestroyNotify |
| Many methods in classes derived from GObject take a callback function and
a destructor function which is called to free that callback function when
it is no longer required. This function constructs a DestroyNotify function
pointer which when called from C land will free the given Haskell function
pointer (and itself).
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| Weak references
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| type GWeakNotify = FunPtr (Ptr () -> Ptr GObject -> IO ()) |
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| objectWeakref :: GObjectClass o => o -> IO () -> IO GWeakNotify |
| Attach a callback that will be called after the
destroy hooks have been called
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| objectWeakunref :: GObjectClass o => o -> GWeakNotify -> IO () |
| Detach a weak destroy callback function
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| User-Defined Attributes
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| type Quark = CUInt |
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| quarkFromString :: String -> IO Quark |
| Create a unique id based on the given string.
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| objectCreateAttribute :: GObjectClass o => IO (Attr o (Maybe a)) |
Add an attribute to this object.
- The function returns a new attribute that can be set or retrieved from
any GObject. The attribute is wrapped in a Maybe type to reflect
the circumstance when the attribute is not set or if it should be unset.
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| objectSetAttribute :: GObjectClass o => Quark -> o -> Maybe a -> IO () |
| Set the value of an association.
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| objectGetAttributeUnsafe :: GObjectClass o => Quark -> o -> IO (Maybe a) |
Get the value of an association.
- Note that this function may crash the Haskell run-time since the
returned type can be forced to be anything. See objectCreateAttribute
for a safe wrapper around this funciton.
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| Produced by Haddock version 0.8 |
