glib-0.13.2.1: Binding to the GLIB library for Gtk2Hs.

Maintainergtk2hs-users@lists.sourceforge.net
Stabilityprovisional
Portabilityportable (depends on GHC)
Safe HaskellNone
LanguageHaskell98

System.Glib.GObject

Contents

Description

The base object type for all glib objects

Synopsis

Types

newtype GObject Source

Constructors

GObject (ForeignPtr GObject) 

Instances

class GObjectClass o where Source

Methods

toGObject :: o -> GObject Source

Safe upcast.

unsafeCastGObject :: GObject -> o Source

Unchecked downcast.

Instances

mkGObject :: (ForeignPtr GObject -> GObject, FinalizerPtr a) Source

unGObject :: GObject -> ForeignPtr GObject Source

castToGObject :: GObjectClass obj => obj -> obj Source

objectUnref :: FinalizerPtr a Source

Decrease the reference counter of an object

Low level binding functions

All these functions are internal and are only interesting to people writing bindings to GObject-style C libraries.

objectNew :: GType -> [(String, GValue)] -> IO (Ptr GObject) Source

Construct a new object (should rairly be used directly)

objectRef :: GObjectClass obj => Ptr obj -> IO () Source

Increase the reference counter of an object

objectRefSink :: GObjectClass obj => Ptr obj -> IO () Source

Reference and sink an object.

makeNewGObject Source

Arguments

:: GObjectClass obj 
=> (ForeignPtr obj -> obj, FinalizerPtr obj)

constructor for the Haskell object and finalizer C function

-> 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.

constructNewGObject :: GObjectClass obj => (ForeignPtr obj -> obj, FinalizerPtr obj) -> IO (Ptr obj) -> IO obj Source

This function wraps any newly created objects that derives from GInitiallyUnowned also known as objects with "floating-references". The object will be refSink (for glib versions >= 2.10). On non-floating objects, this function behaves exactly the same as "makeNewGObject".

wrapNewGObject :: GObjectClass obj => (ForeignPtr obj -> obj, FinalizerPtr obj) -> IO (Ptr obj) -> IO obj Source

This function wraps any newly created object that does not derived from GInitiallyUnowned (that is a GObject with no floating reference). Since newly created GObjects have a reference count of one, they don't need ref'ing.

GType queries

gTypeGObject :: GType Source

The type constant to check if an instance is of GObject type.

isA :: GObjectClass o => o -> GType -> Bool Source

Determine if this is an instance of a particular GTK type

Callback support

type DestroyNotify = FunPtr (Ptr () -> IO ()) Source

destroyFunPtr :: DestroyNotify Source

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 constants is an address of a functions in C land that will free a function pointer.

destroyStablePtr :: DestroyNotify Source

The address of a function freeing a StablePtr. See destroyFunPtr.

User-Defined Attributes

type Quark = CUInt Source

quarkFromString :: GlibString string => string -> IO Quark Source

Create a unique id based on the given string.

objectCreateAttribute :: GObjectClass o => IO (Attr o (Maybe a)) Source

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.

objectSetAttribute :: GObjectClass o => Quark -> o -> Maybe a -> IO () Source

Set the value of an association.

objectGetAttributeUnsafe :: GObjectClass o => Quark -> o -> IO (Maybe a) Source

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.