This is the signature of marshaller functions, required to marshall arrays of parameter values to signal emissions into C language callback invocations. It is merely an alias to #GClosureMarshal since the #GClosure mechanism takes over responsibility of actual function invocation for the signal system. This is the signature of va_list marshaller functions, an optional marshaller that can be used in some situations to avoid marshalling the signal argument into GValues. A numerical value which represents the unique identifier of a registered type.

A convenience macro to ease adding private data to instances of a new type in the @_C_ section of G_DEFINE_TYPE_WITH_CODE() or G_DEFINE_ABSTRACT_TYPE_WITH_CODE(). For instance: |[ typedef struct _MyObject MyObject; typedef struct _MyObjectClass MyObjectClass; typedef struct { gint foo; gint bar; } MyObjectPrivate; G_DEFINE_TYPE_WITH_CODE (MyObject, my_object, G_TYPE_OBJECT, G_ADD_PRIVATE (MyObject)) ]| Will add MyObjectPrivate as the private data to any instance of the MyObject type. G_DEFINE_TYPE_* macros will automatically create a private function based on the arguments to this macro, which can be used to safely retrieve the private data from an instance of the type; for instance: |[ gint my_object_get_foo (MyObject *obj) { MyObjectPrivate *priv = my_object_get_instance_private (obj); g_return_val_if_fail (MY_IS_OBJECT (obj), 0); return priv->foo; } void my_object_set_bar (MyObject *obj, gint bar) { MyObjectPrivate *priv = my_object_get_instance_private (obj); g_return_if_fail (MY_IS_OBJECT (obj)); if (priv->bar != bar) priv->bar = bar; } ]| Note that this macro can only be used together with the G_DEFINE_TYPE_* macros, since it depends on variable names from those macros. Also note that private structs added with these macros must have a struct name of the form `TypeNamePrivate`. It is safe to call the `_get_instance_private` function on %NULL or invalid objects since it's only adding an offset to the instance pointer. In that case the returned pointer must not be dereferenced. the name of the type in CamelCase

A convenience macro to ease adding private data to instances of a new dynamic type in the @_C_ section of G_DEFINE_DYNAMIC_TYPE_EXTENDED(). See G_ADD_PRIVATE() for details, it is similar but for static types. Note that this macro can only be used together with the G_DEFINE_DYNAMIC_TYPE_EXTENDED macros, since it depends on variable names from that macro. the name of the type in CamelCase

A callback function used by the type system to finalize those portions of a derived types class structure that were setup from the corresponding GBaseInitFunc() function. Class finalization basically works the inverse way in which class initialization is performed. See GClassInitFunc() for a discussion of the class initialization process.

The #GTypeClass structure to finalize A callback function used by the type system to do base initialization of the class structures of derived types. It is called as part of the initialization process of all derived classes and should reallocate or reset all dynamic class members copied over from the parent class. For example, class members (such as strings) that are not sufficiently handled by a plain memory copy of the parent class into the derived class have to be altered. See GClassInitFunc() for a discussion of the class initialization process.

The #GTypeClass structure to initialize #GBinding is the representation of a binding between a property on a #GObject instance (or source) and another property on another #GObject instance (or target). Whenever the source property changes, the same value is applied to the target property; for instance, the following binding: |[ g_object_bind_property (object1, "property-a", object2, "property-b", G_BINDING_DEFAULT); ]| will cause the property named "property-b" of @object2 to be updated every time g_object_set() or the specific accessor changes the value of the property "property-a" of @object1. It is possible to create a bidirectional binding between two properties of two #GObject instances, so that if either property changes, the other is updated as well, for instance: |[ g_object_bind_property (object1, "property-a", object2, "property-b", G_BINDING_BIDIRECTIONAL); ]| will keep the two properties in sync. It is also possible to set a custom transformation function (in both directions, in case of a bidirectional binding) to apply a custom transformation from the source value to the target value before applying it; for instance, the following binding: |[ g_object_bind_property_full (adjustment1, "value", adjustment2, "value", G_BINDING_BIDIRECTIONAL, celsius_to_fahrenheit, fahrenheit_to_celsius, NULL, NULL); ]| will keep the "value" property of the two adjustments in sync; the @celsius_to_fahrenheit function will be called whenever the "value" property of @adjustment1 changes and will transform the current value of the property before applying it to the "value" property of @adjustment2. Vice versa, the @fahrenheit_to_celsius function will be called whenever the "value" property of @adjustment2 changes, and will transform the current value of the property before applying it to the "value" property of @adjustment1. Note that #GBinding does not resolve cycles by itself; a cycle like |[ object1:propertyA -> object2:propertyB object2:propertyB -> object3:propertyC object3:propertyC -> object1:propertyA ]| might lead to an infinite loop. The loop, in this particular case, can be avoided if the objects emit the #GObject::notify signal only if the value has effectively been changed. A binding is implemented using the #GObject::notify signal, so it is susceptible to all the various ways of blocking a signal emission, like g_signal_stop_emission() or g_signal_handler_block(). A binding will be severed, and the resources it allocates freed, whenever either one of the #GObject instances it refers to are finalized, or when the #GBinding instance loses its last reference. Bindings for languages with garbage collection can use g_binding_unbind() to explicitly release a binding between the source and target properties, instead of relying on the last reference on the binding, source, and target instances to drop. #GBinding is available since GObject 2.26 Retrieves the flags passed when constructing the #GBinding.

the #GBindingFlags used by the #GBinding

a #GBinding

Retrieves the #GObject instance used as the source of the binding.

the source #GObject

a #GBinding

Retrieves the name of the property of #GBinding:source used as the source of the binding.

the name of the source property

a #GBinding

Retrieves the #GObject instance used as the target of the binding.

the target #GObject

a #GBinding

Retrieves the name of the property of #GBinding:target used as the target of the binding.

the name of the target property

a #GBinding

Explicitly releases the binding between the source and the target property expressed by @binding. This function will release the reference that is being held on the @binding instance; if you want to hold on to the #GBinding instance after calling g_binding_unbind(), you will need to hold a reference to it.

a #GBinding

Flags to be used to control the #GBinding The #GObject that should be used as the source of the binding The name of the property of #GBinding:source that should be used as the source of the binding. This should be in [canonical form][canonical-parameter-names] to get the best performance. The #GObject that should be used as the target of the binding The name of the property of #GBinding:target that should be used as the target of the binding. This should be in [canonical form][canonical-parameter-names] to get the best performance. Flags to be passed to g_object_bind_property() or g_object_bind_property_full(). This enumeration can be extended at later date. The default binding; if the source property changes, the target property is updated with its value. Bidirectional binding; if either the property of the source or the property of the target changes, the other is updated. Synchronize the values of the source and target properties when creating the binding; the direction of the synchronization is always from the source to the target. If the two properties being bound are booleans, setting one to %TRUE will result in the other being set to %FALSE and vice versa. This flag will only work for boolean properties, and cannot be used when passing custom transformation functions to g_object_bind_property_full(). A function to be called to transform @from_value to @to_value. If this is the @transform_to function of a binding, then @from_value is the @source_property on the @source object, and @to_value is the @target_property on the @target object. If this is the @transform_from function of a %G_BINDING_BIDIRECTIONAL binding, then those roles are reversed.

%TRUE if the transformation was successful, and %FALSE otherwise

a #GBinding the #GValue containing the value to transform the #GValue in which to store the transformed value data passed to the transform function This function is provided by the user and should produce a copy of the passed in boxed structure.

The newly created copy of the boxed structure.

The boxed structure to be copied. This function is provided by the user and should free the boxed structure passed.

The boxed structure to be freed.

Cast a function pointer to a #GCallback. a function pointer.

Checks whether the user data of the #GCClosure should be passed as the first parameter to the callback. See g_cclosure_new_swap(). a #GCClosure

A #GCClosure is a specialization of #GClosure for C function callbacks. the #GClosure the callback function A #GClosureMarshal function for use with signals with handlers that take two boxed pointers as arguments and return a boolean. If you have such a signal, you will probably also need to use an accumulator, such as g_signal_accumulator_true_handled().

A #GClosure. A #GValue to store the return value. May be %NULL if the callback of closure doesn't return a value. The length of the @param_values array. An array of #GValues holding the arguments on which to invoke the callback of closure. The invocation hint given as the last argument to g_closure_invoke(). Additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() The #GVaClosureMarshal equivalent to g_cclosure_marshal_BOOLEAN__BOXED_BOXED().

the #GClosure to which the marshaller belongs a #GValue which can store the returned #gboolean 2 a #GValue array holding instance and arg1 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_BOOLEAN__FLAGS().

the #GClosure to which the marshaller belongs a #GValue, which can store the returned string 3 a #GValue array holding instance, arg1 and arg2 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_STRING__OBJECT_POINTER().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gboolean parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__BOOLEAN().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GBoxed* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__BOXED().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gchar parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__CHAR().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gdouble parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__DOUBLE().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the enumeration parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__ENUM().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the flags parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__FLAGS().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gfloat parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__FLOAT().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gint parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__INT().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #glong parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__LONG().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GObject* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__OBJECT().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GParamSpec* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__PARAM().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gpointer parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__POINTER().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gchar* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__STRING().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #guchar parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__UCHAR().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #guint parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, guint arg1, gpointer arg2, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 3 a #GValue array holding instance, arg1 and arg2 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__UINT_POINTER().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gulong parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__ULONG().

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GVariant* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__VARIANT().

A #GClosure. A #GValue to store the return value. May be %NULL if the callback of closure doesn't return a value. The length of the @param_values array. An array of #GValues holding the arguments on which to invoke the callback of closure. The invocation hint given as the last argument to g_closure_invoke(). Additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() A generic #GVaClosureMarshal function implemented via [libffi](http://sourceware.org/libffi/).

a floating reference to a new #GCClosure

the function to invoke user data to pass to @callback_func destroy notify to be called when @user_data is no longer used A variant of g_cclosure_new() which uses @object as @user_data and calls g_object_watch_closure() on @object and the created closure. This function is useful when you have a callback closely associated with a #GObject, and want the callback to no longer run after the object is is freed.

a new #GCClosure

the function to invoke a #GObject pointer to pass to @callback_func A variant of g_cclosure_new_swap() which uses @object as @user_data and calls g_object_watch_closure() on @object and the created closure. This function is useful when you have a callback closely associated with a #GObject, and want the callback to no longer run after the object is is freed.

a new #GCClosure

the function to invoke a #GObject pointer to pass to @callback_func Creates a new closure which invokes @callback_func with @user_data as the first parameter. @destroy_data will be called as a finalize notifier on the #GClosure.

a floating reference to a new #GCClosure

the function to invoke user data to pass to @callback_func destroy notify to be called when @user_data is no longer used

Check if the closure still needs a marshaller. See g_closure_set_marshal(). a #GClosure

Get the total number of notifiers connected with the closure @cl. The count includes the meta marshaller, the finalize and invalidate notifiers and the marshal guards. Note that each guard counts as two notifiers. See g_closure_set_meta_marshal(), g_closure_add_finalize_notifier(), g_closure_add_invalidate_notifier() and g_closure_add_marshal_guards(). a #GClosure

The type used for callback functions in structure definitions and function signatures. This doesn't mean that all callback functions must take no parameters and return void. The required signature of a callback function is determined by the context in which is used (e.g. the signal to which it is connected). Use G_CALLBACK() to cast the callback function to a #GCallback.

A callback function used by the type system to finalize a class. This function is rarely needed, as dynamically allocated class resources should be handled by GBaseInitFunc() and GBaseFinalizeFunc(). Also, specification of a GClassFinalizeFunc() in the #GTypeInfo structure of a static type is invalid, because classes of static types will never be finalized (they are artificially kept alive when their reference count drops to zero).

The #GTypeClass structure to finalize The @class_data member supplied via the #GTypeInfo structure A callback function used by the type system to initialize the class of a specific type. This function should initialize all static class members. The initialization process of a class involves: - Copying common members from the parent class over to the derived class structure. - Zero initialization of the remaining members not copied over from the parent class. - Invocation of the GBaseInitFunc() initializers of all parent types and the class' type. - Invocation of the class' GClassInitFunc() initializer. Since derived classes are partially initialized through a memory copy of the parent class, the general rule is that GBaseInitFunc() and GBaseFinalizeFunc() should take care of necessary reinitialization and release of those class members that were introduced by the type that specified these GBaseInitFunc()/GBaseFinalizeFunc(). GClassInitFunc() should only care about initializing static class members, while dynamic class members (such as allocated strings or reference counted resources) are better handled by a GBaseInitFunc() for this type, so proper initialization of the dynamic class members is performed for class initialization of derived types as well. An example may help to correspond the intend of the different class initializers: |[ typedef struct { GObjectClass parent_class; gint static_integer; gchar *dynamic_string; } TypeAClass; static void type_a_base_class_init (TypeAClass *class) { class->dynamic_string = g_strdup ("some string"); } static void type_a_base_class_finalize (TypeAClass *class) { g_free (class->dynamic_string); } static void type_a_class_init (TypeAClass *class) { class->static_integer = 42; } typedef struct { TypeAClass parent_class; gfloat static_float; GString *dynamic_gstring; } TypeBClass; static void type_b_base_class_init (TypeBClass *class) { class->dynamic_gstring = g_string_new ("some other string"); } static void type_b_base_class_finalize (TypeBClass *class) { g_string_free (class->dynamic_gstring); } static void type_b_class_init (TypeBClass *class) { class->static_float = 3.14159265358979323846; } ]| Initialization of TypeBClass will first cause initialization of TypeAClass (derived classes reference their parent classes, see g_type_class_ref() on this). Initialization of TypeAClass roughly involves zero-initializing its fields, then calling its GBaseInitFunc() type_a_base_class_init() to allocate its dynamic members (dynamic_string), and finally calling its GClassInitFunc() type_a_class_init() to initialize its static members (static_integer). The first step in the initialization process of TypeBClass is then a plain memory copy of the contents of TypeAClass into TypeBClass and zero-initialization of the remaining fields in TypeBClass. The dynamic members of TypeAClass within TypeBClass now need reinitialization which is performed by calling type_a_base_class_init() with an argument of TypeBClass. After that, the GBaseInitFunc() of TypeBClass, type_b_base_class_init() is called to allocate the dynamic members of TypeBClass (dynamic_gstring), and finally the GClassInitFunc() of TypeBClass, type_b_class_init(), is called to complete the initialization process with the static members (static_float). Corresponding finalization counter parts to the GBaseInitFunc() functions have to be provided to release allocated resources at class finalization time.

The #GTypeClass structure to initialize. The @class_data member supplied via the #GTypeInfo structure. A #GClosure represents a callback supplied by the programmer. It will generally comprise a function of some kind and a marshaller used to call it. It is the responsibility of the marshaller to convert the arguments for the invocation from #GValues into a suitable form, perform the callback on the converted arguments, and transform the return value back into a #GValue. In the case of C programs, a closure usually just holds a pointer to a function and maybe a data argument, and the marshaller converts between #GValue and native C types. The GObject library provides the #GCClosure type for this purpose. Bindings for other languages need marshallers which convert between #GValues and suitable representations in the runtime of the language in order to use functions written in that language as callbacks. Use g_closure_set_marshal() to set the marshaller on such a custom closure implementation. Within GObject, closures play an important role in the implementation of signals. When a signal is registered, the @c_marshaller argument to g_signal_new() specifies the default C marshaller for any closure which is connected to this signal. GObject provides a number of C marshallers for this purpose, see the g_cclosure_marshal_*() functions. Additional C marshallers can be generated with the [glib-genmarshal][glib-genmarshal] utility. Closures can be explicitly connected to signals with g_signal_connect_closure(), but it usually more convenient to let GObject create a closure automatically by using one of the g_signal_connect_*() functions which take a callback function/user data pair. Using closures has a number of important advantages over a simple callback function/data pointer combination: - Closures allow the callee to get the types of the callback parameters, which means that language bindings don't have to write individual glue for each callback type. - The reference counting of #GClosure makes it easy to handle reentrancy right; if a callback is removed while it is being invoked, the closure and its parameters won't be freed until the invocation finishes. - g_closure_invalidate() and invalidation notifiers allow callbacks to be automatically removed when the objects they point to go away. Indicates whether the closure is currently being invoked with g_closure_invoke() Indicates whether the closure has been invalidated by g_closure_invalidate()

A variant of g_closure_new_simple() which stores @object in the @data field of the closure and calls g_object_watch_closure() on @object and the created closure. This function is mainly useful when implementing new types of closures.

a newly allocated #GClosure

the size of the structure to allocate, must be at least `sizeof (GClosure)` a #GObject pointer to store in the @data field of the newly allocated #GClosure Allocates a struct of the given size and initializes the initial part as a #GClosure. This function is mainly useful when implementing new types of closures. |[ typedef struct _MyClosure MyClosure; struct _MyClosure { GClosure closure; // extra data goes here }; static void my_closure_finalize (gpointer notify_data, GClosure *closure) { MyClosure *my_closure = (MyClosure *)closure; // free extra data here } MyClosure *my_closure_new (gpointer data) { GClosure *closure; MyClosure *my_closure; closure = g_closure_new_simple (sizeof (MyClosure), data); my_closure = (MyClosure *) closure; // initialize extra data here g_closure_add_finalize_notifier (closure, notify_data, my_closure_finalize); return my_closure; } ]|

a floating reference to a new #GClosure

the size of the structure to allocate, must be at least `sizeof (GClosure)` data to store in the @data field of the newly allocated #GClosure Registers a finalization notifier which will be called when the reference count of @closure goes down to 0. Multiple finalization notifiers on a single closure are invoked in unspecified order. If a single call to g_closure_unref() results in the closure being both invalidated and finalized, then the invalidate notifiers will be run before the finalize notifiers.

a #GClosure

data to pass to @notify_func the callback function to register Registers an invalidation notifier which will be called when the @closure is invalidated with g_closure_invalidate(). Invalidation notifiers are invoked before finalization notifiers, in an unspecified order.

a #GClosure

data to pass to @notify_func the callback function to register Adds a pair of notifiers which get invoked before and after the closure callback, respectively. This is typically used to protect the extra arguments for the duration of the callback. See g_object_watch_closure() for an example of marshal guards.

a #GClosure

data to pass to @pre_marshal_notify a function to call before the closure callback data to pass to @post_marshal_notify a function to call after the closure callback Sets a flag on the closure to indicate that its calling environment has become invalid, and thus causes any future invocations of g_closure_invoke() on this @closure to be ignored. Also, invalidation notifiers installed on the closure will be called at this point. Note that unless you are holding a reference to the closure yourself, the invalidation notifiers may unref the closure and cause it to be destroyed, so if you need to access the closure after calling g_closure_invalidate(), make sure that you've previously called g_closure_ref(). Note that g_closure_invalidate() will also be called when the reference count of a closure drops to zero (unless it has already been invalidated before).

#GClosure to invalidate

Invokes the closure, i.e. executes the callback represented by the @closure.

a #GClosure

a #GValue to store the return value. May be %NULL if the callback of @closure doesn't return a value. the length of the @param_values array an array of #GValues holding the arguments on which to invoke the callback of @closure a context-dependent invocation hint Increments the reference count on a closure to force it staying alive while the caller holds a pointer to it.

The @closure passed in, for convenience

#GClosure to increment the reference count on

Removes a finalization notifier. Notice that notifiers are automatically removed after they are run.

a #GClosure

data which was passed to g_closure_add_finalize_notifier() when registering @notify_func the callback function to remove Removes an invalidation notifier. Notice that notifiers are automatically removed after they are run.

a #GClosure

data which was passed to g_closure_add_invalidate_notifier() when registering @notify_func the callback function to remove Sets the marshaller of @closure. The `marshal_data` of @marshal provides a way for a meta marshaller to provide additional information to the marshaller. (See g_closure_set_meta_marshal().) For GObject's C predefined marshallers (the g_cclosure_marshal_*() functions), what it provides is a callback function to use instead of @closure->callback.

a #GClosure

a #GClosureMarshal function Sets the meta marshaller of @closure. A meta marshaller wraps @closure->marshal and modifies the way it is called in some fashion. The most common use of this facility is for C callbacks. The same marshallers (generated by [glib-genmarshal][glib-genmarshal]), are used everywhere, but the way that we get the callback function differs. In most cases we want to use @closure->callback, but in other cases we want to use some different technique to retrieve the callback function. For example, class closures for signals (see g_signal_type_cclosure_new()) retrieve the callback function from a fixed offset in the class structure. The meta marshaller retrieves the right callback and passes it to the marshaller as the @marshal_data argument.

a #GClosure

context-dependent data to pass to @meta_marshal a #GClosureMarshal function Takes over the initial ownership of a closure. Each closure is initially created in a "floating" state, which means that the initial reference count is not owned by any caller. g_closure_sink() checks to see if the object is still floating, and if so, unsets the floating state and decreases the reference count. If the closure is not floating, g_closure_sink() does nothing. The reason for the existence of the floating state is to prevent cumbersome code sequences like: |[ closure = g_cclosure_new (cb_func, cb_data); g_source_set_closure (source, closure); g_closure_unref (closure); // GObject doesn't really need this ]| Because g_source_set_closure() (and similar functions) take ownership of the initial reference count, if it is unowned, we instead can write: |[ g_source_set_closure (source, g_cclosure_new (cb_func, cb_data)); ]| Generally, this function is used together with g_closure_ref(). An example of storing a closure for later notification looks like: |[ static GClosure *notify_closure = NULL; void foo_notify_set_closure (GClosure *closure) { if (notify_closure) g_closure_unref (notify_closure); notify_closure = closure; if (notify_closure) { g_closure_ref (notify_closure); g_closure_sink (notify_closure); } } ]| Because g_closure_sink() may decrement the reference count of a closure (if it hasn't been called on @closure yet) just like g_closure_unref(), g_closure_ref() should be called prior to this function.

#GClosure to decrement the initial reference count on, if it's still being held

Decrements the reference count of a closure after it was previously incremented by the same caller. If no other callers are using the closure, then the closure will be destroyed and freed.

#GClosure to decrement the reference count on

The type used for marshaller functions.

the #GClosure to which the marshaller belongs a #GValue to store the return value. May be %NULL if the callback of @closure doesn't return a value. the length of the @param_values array an array of #GValues holding the arguments on which to invoke the callback of @closure the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() The type used for the various notification callbacks which can be registered on closures.

data specified when registering the notification callback the #GClosure on which the notification is emitted The connection flags are used to specify the behaviour of a signal's connection. whether the handler should be called before or after the default handler of the signal. whether the instance and data should be swapped when calling the handler; see g_signal_connect_swapped() for an example.

A convenience macro for emitting the usual declarations in the header file for a type which is intended to be subclassed. You might use it in a header as follows: |[ #ifndef _gtk_frobber_h_ #define _gtk_frobber_h_ #define GTK_TYPE_FROBBER gtk_frobber_get_type () GDK_AVAILABLE_IN_3_12 G_DECLARE_DERIVABLE_TYPE (GtkFrobber, gtk_frobber, GTK, FROBBER, GtkWidget) struct _GtkFrobberClass { GtkWidgetClass parent_class; void (* handle_frob) (GtkFrobber *frobber, guint n_frobs); gpointer padding[12]; }; GtkWidget * gtk_frobber_new (void); ... #endif ]| This results in the following things happening: - the usual gtk_frobber_get_type() function is declared with a return type of #GType - the GtkFrobber struct is created with GtkWidget as the first and only item. You are expected to use a private structure from your .c file to store your instance variables. - the GtkFrobberClass type is defined as a typedef to struct _GtkFrobberClass, which is left undefined. You should do this from the header file directly after you use the macro. - the GTK_FROBBER() and GTK_FROBBER_CLASS() casts are emitted as static inline functions along with the GTK_IS_FROBBER() and GTK_IS_FROBBER_CLASS() type checking functions and GTK_FROBBER_GET_CLASS() function. - g_autoptr() support being added for your type, based on the type of your parent class You can only use this function if your parent type also supports g_autoptr(). Because the type macro (GTK_TYPE_FROBBER in the above example) is not a callable, you must continue to manually define this as a macro for yourself. The declaration of the _get_type() function is the first thing emitted by the macro. This allows this macro to be used in the usual way with export control and API versioning macros. If you are writing a library, it is important to note that it is possible to convert a type from using G_DECLARE_FINAL_TYPE() to G_DECLARE_DERIVABLE_TYPE() without breaking API or ABI. As a precaution, you should therefore use G_DECLARE_FINAL_TYPE() until you are sure that it makes sense for your class to be subclassed. Once a class structure has been exposed it is not possible to change its size or remove or reorder items without breaking the API and/or ABI. If you want to declare your own class structure, use G_DECLARE_DERIVABLE_TYPE(). If you want to declare a class without exposing the class or instance structures, use G_DECLARE_FINAL_TYPE(). If you must use G_DECLARE_DERIVABLE_TYPE() you should be sure to include some padding at the bottom of your class structure to leave space for the addition of future virtual functions. The name of the new type, in camel case (like GtkWidget) The name of the new type in lowercase, with words separated by '_' (like 'gtk_widget') The name of the module, in all caps (like 'GTK') The bare name of the type, in all caps (like 'WIDGET') the name of the parent type, in camel case (like GtkWidget)

A convenience macro for emitting the usual declarations in the header file for a type which is not (at the present time) intended to be subclassed. You might use it in a header as follows: |[ #ifndef _myapp_window_h_ #define _myapp_window_h_ #include <gtk/gtk.h> #define MY_APP_TYPE_WINDOW my_app_window_get_type () G_DECLARE_FINAL_TYPE (MyAppWindow, my_app_window, MY_APP, WINDOW, GtkWindow) MyAppWindow * my_app_window_new (void); ... #endif ]| This results in the following things happening: - the usual my_app_window_get_type() function is declared with a return type of #GType - the MyAppWindow types is defined as a typedef of struct _MyAppWindow. The struct itself is not defined and should be defined from the .c file before G_DEFINE_TYPE() is used. - the MY_APP_WINDOW() cast is emitted as static inline function along with the MY_APP_IS_WINDOW() type checking function - the MyAppWindowClass type is defined as a struct containing GtkWindowClass. This is done for the convenience of the person defining the type and should not be considered to be part of the ABI. In particular, without a firm declaration of the instance structure, it is not possible to subclass the type and therefore the fact that the size of the class structure is exposed is not a concern and it can be freely changed at any point in the future. - g_autoptr() support being added for your type, based on the type of your parent class You can only use this function if your parent type also supports g_autoptr(). Because the type macro (MY_APP_TYPE_WINDOW in the above example) is not a callable, you must continue to manually define this as a macro for yourself. The declaration of the _get_type() function is the first thing emitted by the macro. This allows this macro to be used in the usual way with export control and API versioning macros. If you want to declare your own class structure, use G_DECLARE_DERIVABLE_TYPE(). If you are writing a library, it is important to note that it is possible to convert a type from using G_DECLARE_FINAL_TYPE() to G_DECLARE_DERIVABLE_TYPE() without breaking API or ABI. As a precaution, you should therefore use G_DECLARE_FINAL_TYPE() until you are sure that it makes sense for your class to be subclassed. Once a class structure has been exposed it is not possible to change its size or remove or reorder items without breaking the API and/or ABI. The name of the new type, in camel case (like GtkWidget) The name of the new type in lowercase, with words separated by '_' (like 'gtk_widget') The name of the module, in all caps (like 'GTK') The bare name of the type, in all caps (like 'WIDGET') the name of the parent type, in camel case (like GtkWidget)

A convenience macro for emitting the usual declarations in the header file for a GInterface type. You might use it in a header as follows: |[ #ifndef _my_model_h_ #define _my_model_h_ #define MY_TYPE_MODEL my_model_get_type () GDK_AVAILABLE_IN_3_12 G_DECLARE_INTERFACE (MyModel, my_model, MY, MODEL, GObject) struct _MyModelInterface { GTypeInterface g_iface; gpointer (* get_item) (MyModel *model); }; gpointer my_model_get_item (MyModel *model); ... #endif ]| This results in the following things happening: - the usual my_model_get_type() function is declared with a return type of #GType - the MyModelInterface type is defined as a typedef to struct _MyModelInterface, which is left undefined. You should do this from the header file directly after you use the macro. - the MY_MODEL() cast is emitted as static inline functions along with the MY_IS_MODEL() type checking function and MY_MODEL_GET_IFACE() function. - g_autoptr() support being added for your type, based on your prerequisite type. You can only use this function if your prerequisite type also supports g_autoptr(). Because the type macro (MY_TYPE_MODEL in the above example) is not a callable, you must continue to manually define this as a macro for yourself. The declaration of the _get_type() function is the first thing emitted by the macro. This allows this macro to be used in the usual way with export control and API versioning macros. The name of the new type, in camel case (like GtkWidget) The name of the new type in lowercase, with words separated by '_' (like 'gtk_widget') The name of the module, in all caps (like 'GTK') The bare name of the type, in all caps (like 'WIDGET') the name of the prerequisite type, in camel case (like GtkWidget)

A convenience macro for type implementations. Similar to G_DEFINE_TYPE(), but defines an abstract type. See G_DEFINE_TYPE_EXTENDED() for an example. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type.

A convenience macro for type implementations. Similar to G_DEFINE_TYPE_WITH_CODE(), but defines an abstract type and allows you to insert custom code into the *_get_type() function, e.g. interface implementations via G_IMPLEMENT_INTERFACE(). See G_DEFINE_TYPE_EXTENDED() for an example. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type. Custom code that gets inserted in the @type_name_get_type() function.

Similar to G_DEFINE_TYPE_WITH_PRIVATE(), but defines an abstract type. See G_DEFINE_TYPE_EXTENDED() for an example. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type.

A convenience macro for boxed type implementations, which defines a type_name_get_type() function registering the boxed type. The name of the new type, in Camel case The name of the new type, in lowercase, with words separated by '_' the #GBoxedCopyFunc for the new type the #GBoxedFreeFunc for the new type

A convenience macro for boxed type implementations. Similar to G_DEFINE_BOXED_TYPE(), but allows to insert custom code into the type_name_get_type() function, e.g. to register value transformations with g_value_register_transform_func(), for instance: |[ G_DEFINE_BOXED_TYPE_WITH_CODE (GdkRectangle, gdk_rectangle, gdk_rectangle_copy, gdk_rectangle_free, register_rectangle_transform_funcs (g_define_type_id)) ]| Similarly to the %G_DEFINE_TYPE family of macros, the #GType of the newly defined boxed type is exposed in the `g_define_type_id` variable. The name of the new type, in Camel case The name of the new type, in lowercase, with words separated by '_' the #GBoxedCopyFunc for the new type the #GBoxedFreeFunc for the new type Custom code that gets inserted in the *_get_type() function

A convenience macro for dynamic type implementations, which declares a class initialization function, an instance initialization function (see #GTypeInfo for information about these) and a static variable named `t_n`_parent_class pointing to the parent class. Furthermore, it defines a `*_get_type()` and a static `*_register_type()` functions for use in your `module_init()`. See G_DEFINE_DYNAMIC_TYPE_EXTENDED() for an example. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type.

A more general version of G_DEFINE_DYNAMIC_TYPE() which allows to specify #GTypeFlags and custom code. |[ G_DEFINE_DYNAMIC_TYPE_EXTENDED (GtkGadget, gtk_gadget, GTK_TYPE_THING, 0, G_IMPLEMENT_INTERFACE_DYNAMIC (TYPE_GIZMO, gtk_gadget_gizmo_init)); ]| expands to |[ static void gtk_gadget_init (GtkGadget *self); static void gtk_gadget_class_init (GtkGadgetClass *klass); static void gtk_gadget_class_finalize (GtkGadgetClass *klass); static gpointer gtk_gadget_parent_class = NULL; static GType gtk_gadget_type_id = 0; static void gtk_gadget_class_intern_init (gpointer klass) { gtk_gadget_parent_class = g_type_class_peek_parent (klass); gtk_gadget_class_init ((GtkGadgetClass*) klass); } GType gtk_gadget_get_type (void) { return gtk_gadget_type_id; } static void gtk_gadget_register_type (GTypeModule *type_module) { const GTypeInfo g_define_type_info = { sizeof (GtkGadgetClass), (GBaseInitFunc) NULL, (GBaseFinalizeFunc) NULL, (GClassInitFunc) gtk_gadget_class_intern_init, (GClassFinalizeFunc) gtk_gadget_class_finalize, NULL, // class_data sizeof (GtkGadget), 0, // n_preallocs (GInstanceInitFunc) gtk_gadget_init, NULL // value_table }; gtk_gadget_type_id = g_type_module_register_type (type_module, GTK_TYPE_THING, "GtkGadget", &g_define_type_info, (GTypeFlags) flags); { const GInterfaceInfo g_implement_interface_info = { (GInterfaceInitFunc) gtk_gadget_gizmo_init }; g_type_module_add_interface (type_module, g_define_type_id, TYPE_GIZMO, &g_implement_interface_info); } } ]| The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type. #GTypeFlags to pass to g_type_module_register_type() Custom code that gets inserted in the *_get_type() function.

A convenience macro for #GTypeInterface definitions, which declares a default vtable initialization function and defines a *_get_type() function. The macro expects the interface initialization function to have the name `t_n ## _default_init`, and the interface structure to have the name `TN ## Interface`. The initialization function has signature `static void t_n ## _default_init (TypeName##Interface *klass);`, rather than the full #GInterfaceInitFunc signature, for brevity and convenience. If you need to use an initialization function with an `iface_data` argument, you must write the #GTypeInterface definitions manually. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the prerequisite type for the interface, or 0 (%G_TYPE_INVALID) for no prerequisite type.

A convenience macro for #GTypeInterface definitions. Similar to G_DEFINE_INTERFACE(), but allows you to insert custom code into the *_get_type() function, e.g. additional interface implementations via G_IMPLEMENT_INTERFACE(), or additional prerequisite types. See G_DEFINE_TYPE_EXTENDED() for a similar example using G_DEFINE_TYPE_WITH_CODE(). The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the prerequisite type for the interface, or 0 (%G_TYPE_INVALID) for no prerequisite type. Custom code that gets inserted in the *_get_type() function.

A convenience macro for pointer type implementations, which defines a type_name_get_type() function registering the pointer type. The name of the new type, in Camel case The name of the new type, in lowercase, with words separated by '_'

A convenience macro for pointer type implementations. Similar to G_DEFINE_POINTER_TYPE(), but allows to insert custom code into the type_name_get_type() function. The name of the new type, in Camel case The name of the new type, in lowercase, with words separated by '_' Custom code that gets inserted in the *_get_type() function

The most general convenience macro for type implementations, on which G_DEFINE_TYPE(), etc are based. |[ G_DEFINE_TYPE_EXTENDED (GtkGadget, gtk_gadget, GTK_TYPE_WIDGET, 0, G_ADD_PRIVATE (GtkGadget) G_IMPLEMENT_INTERFACE (TYPE_GIZMO, gtk_gadget_gizmo_init)); ]| expands to |[ static void gtk_gadget_init (GtkGadget *self); static void gtk_gadget_class_init (GtkGadgetClass *klass); static gpointer gtk_gadget_parent_class = NULL; static gint GtkGadget_private_offset; static void gtk_gadget_class_intern_init (gpointer klass) { gtk_gadget_parent_class = g_type_class_peek_parent (klass); if (GtkGadget_private_offset != 0) g_type_class_adjust_private_offset (klass, &GtkGadget_private_offset); gtk_gadget_class_init ((GtkGadgetClass*) klass); } static inline gpointer gtk_gadget_get_instance_private (GtkGadget *self) { return (G_STRUCT_MEMBER_P (self, GtkGadget_private_offset)); } GType gtk_gadget_get_type (void) { static volatile gsize g_define_type_id__volatile = 0; if (g_once_init_enter (&g_define_type_id__volatile)) { GType g_define_type_id = g_type_register_static_simple (GTK_TYPE_WIDGET, g_intern_static_string ("GtkGadget"), sizeof (GtkGadgetClass), (GClassInitFunc) gtk_gadget_class_intern_init, sizeof (GtkGadget), (GInstanceInitFunc) gtk_gadget_init, 0); { GtkGadget_private_offset = g_type_add_instance_private (g_define_type_id, sizeof (GtkGadgetPrivate)); } { const GInterfaceInfo g_implement_interface_info = { (GInterfaceInitFunc) gtk_gadget_gizmo_init }; g_type_add_interface_static (g_define_type_id, TYPE_GIZMO, &g_implement_interface_info); } g_once_init_leave (&g_define_type_id__volatile, g_define_type_id); } return g_define_type_id__volatile; } ]| The only pieces which have to be manually provided are the definitions of the instance and class structure and the definitions of the instance and class init functions. The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type. #GTypeFlags to pass to g_type_register_static() Custom code that gets inserted in the *_get_type() function.

A convenience macro for type implementations. Similar to G_DEFINE_TYPE(), but allows you to insert custom code into the *_get_type() function, e.g. interface implementations via G_IMPLEMENT_INTERFACE(). See G_DEFINE_TYPE_EXTENDED() for an example. The name of the new type, in Camel case. The name of the new type in lowercase, with words separated by '_'. The #GType of the parent type. Custom code that gets inserted in the *_get_type() function.

A convenience macro for type implementations, which declares a class initialization function, an instance initialization function (see #GTypeInfo for information about these), a static variable named `t_n_parent_class` pointing to the parent class, and adds private instance data to the type. Furthermore, it defines a *_get_type() function. See G_DEFINE_TYPE_EXTENDED() for an example. Note that private structs added with this macros must have a struct name of the form @TN Private. The private instance data can be retrieved using the automatically generated getter function `t_n_get_instance_private()`. See also: G_ADD_PRIVATE() The name of the new type, in Camel case. The name of the new type, in lowercase, with words separated by '_'. The #GType of the parent type.

Casts a derived #GEnumClass structure into a #GEnumClass structure. a valid #GEnumClass

Get the type identifier from a given #GEnumClass structure. a #GEnumClass

Get the static type name from a given #GEnumClass structure. a #GEnumClass

The class of an enumeration type holds information about its possible values. the parent class the smallest possible value. the largest possible value. the number of possible values. an array of #GEnumValue structs describing the individual values. A structure which contains a single enum value, its name, and its nickname. the enum value the name of the value the nickname of the value

Casts a derived #GFlagsClass structure into a #GFlagsClass structure. a valid #GFlagsClass

Get the type identifier from a given #GFlagsClass structure. a #GFlagsClass

Get the static type name from a given #GFlagsClass structure. a #GFlagsClass

The class of a flags type holds information about its possible values. the parent class a mask covering all possible values. the number of possible values. an array of #GFlagsValue structs describing the individual values. A structure which contains a single flags value, its name, and its nickname. the flags value the name of the value the nickname of the value

A convenience macro to ease interface addition in the `_C_` section of G_DEFINE_TYPE_WITH_CODE() or G_DEFINE_ABSTRACT_TYPE_WITH_CODE(). See G_DEFINE_TYPE_EXTENDED() for an example. Note that this macro can only be used together with the G_DEFINE_TYPE_* macros, since it depends on variable names from those macros. The #GType of the interface to add The interface init function, of type #GInterfaceInitFunc

A convenience macro to ease interface addition in the @_C_ section of G_DEFINE_DYNAMIC_TYPE_EXTENDED(). See G_DEFINE_DYNAMIC_TYPE_EXTENDED() for an example. Note that this macro can only be used together with the G_DEFINE_DYNAMIC_TYPE_EXTENDED macros, since it depends on variable names from that macro. The #GType of the interface to add The interface init function

Casts a #GInitiallyUnowned or derived pointer into a (GInitiallyUnowned*) pointer. Depending on the current debugging level, this function may invoke certain runtime checks to identify invalid casts. Object which is subject to casting.

Casts a derived #GInitiallyUnownedClass structure into a #GInitiallyUnownedClass structure. a valid #GInitiallyUnownedClass

Get the class structure associated to a #GInitiallyUnowned instance. a #GInitiallyUnowned instance.

Checks whether @class "is a" valid #GEnumClass structure of type %G_TYPE_ENUM or derived. a #GEnumClass

Checks whether @class "is a" valid #GFlagsClass structure of type %G_TYPE_FLAGS or derived. a #GFlagsClass

Checks whether a valid #GTypeInstance pointer is of type %G_TYPE_INITIALLY_UNOWNED. Instance to check for being a %G_TYPE_INITIALLY_UNOWNED.

Checks whether @class "is a" valid #GInitiallyUnownedClass structure of type %G_TYPE_INITIALLY_UNOWNED or derived. a #GInitiallyUnownedClass

Checks whether a valid #GTypeInstance pointer is of type %G_TYPE_OBJECT. Instance to check for being a %G_TYPE_OBJECT.

Checks whether @class "is a" valid #GObjectClass structure of type %G_TYPE_OBJECT or derived. a #GObjectClass

Checks whether @pspec "is a" valid #GParamSpec structure of type %G_TYPE_PARAM or derived. a #GParamSpec

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_BOOLEAN. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_BOXED. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_CHAR. a valid #GParamSpec instance

Checks whether @pclass "is a" valid #GParamSpecClass structure of type %G_TYPE_PARAM or derived. a #GParamSpecClass

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_DOUBLE. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_ENUM. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_FLAGS. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_FLOAT. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_GTYPE. a #GParamSpec

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_INT. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_INT64. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_LONG. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_OBJECT. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_OVERRIDE. a #GParamSpec

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_PARAM. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_POINTER. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_STRING. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_UCHAR. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_UINT. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_UINT64. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_ULONG. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_UNICHAR. a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_VALUE_ARRAY.

Use #GArray instead of #GValueArray

a valid #GParamSpec instance

Checks whether the given #GParamSpec is of type %G_TYPE_PARAM_VARIANT. a #GParamSpec

Checks if @value is a valid and initialized #GValue structure. A #GValue structure.

All the fields in the GInitiallyUnowned structure are private to the #GInitiallyUnowned implementation and should never be accessed directly. The class structure for the GInitiallyUnowned type. the parent class

a #GObject

A callback function used by the type system to initialize a new instance of a type. This function initializes all instance members and allocates any resources required by it. Initialization of a derived instance involves calling all its parent types instance initializers, so the class member of the instance is altered during its initialization to always point to the class that belongs to the type the current initializer was introduced for. The extended members of @instance are guaranteed to have been filled with zeros before this function is called.

The instance to initialize The class of the type the instance is created for A callback function used by the type system to finalize an interface. This function should destroy any internal data and release any resources allocated by the corresponding GInterfaceInitFunc() function.

The interface structure to finalize The @interface_data supplied via the #GInterfaceInfo structure A structure that provides information to the type system which is used specifically for managing interface types. location of the interface initialization function location of the interface finalization function user-supplied data passed to the interface init/finalize functions A callback function used by the type system to initialize a new interface. This function should initialize all internal data and allocate any resources required by the interface. The members of @iface_data are guaranteed to have been filled with zeros before this function is called.

The interface structure to initialize The @interface_data supplied via the #GInterfaceInfo structure

Casts a #GObject or derived pointer into a (GObject*) pointer. Depending on the current debugging level, this function may invoke certain runtime checks to identify invalid casts. Object which is subject to casting.

Casts a derived #GObjectClass structure into a #GObjectClass structure. a valid #GObjectClass

Return the name of a class structure's type. a valid #GObjectClass

Get the type id of a class structure. a valid #GObjectClass

Get the class structure associated to a #GObject instance. a #GObject instance.

Get the type id of an object. Object to return the type id for.

Get the name of an object's type. Object to return the type name for.

This macro should be used to emit a standard warning about unexpected properties in set_property() and get_property() implementations. the #GObject on which set_property() or get_property() was called the numeric id of the property the #GParamSpec of the property

All the fields in the GObject structure are private to the #GObject implementation and should never be accessed directly. Creates a new instance of a #GObject subtype and sets its properties. Construction parameters (see #G_PARAM_CONSTRUCT, #G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values. Any private data for the object is guaranteed to be initialized with zeros, as per g_type_create_instance(). Note that in C, small integer types in variable argument lists are promoted up to #gint or #guint as appropriate, and read back accordingly. #gint is 32 bits on every platform on which GLib is currently supported. This means that you can use C expressions of type #gint with g_object_new() and properties of type #gint or #guint or smaller. Specifically, you can use integer literals with these property types. When using property types of #gint64 or #guint64, you must ensure that the value that you provide is 64 bit. This means that you should use a cast or make use of the %G_GINT64_CONSTANT or %G_GUINT64_CONSTANT macros. Similarly, #gfloat is promoted to #gdouble, so you must ensure that the value you provide is a #gdouble, even for a property of type #gfloat.

a new instance of @object_type

the type id of the #GObject subtype to instantiate the name of the first property the value of the first property, followed optionally by more name/value pairs, followed by %NULL Creates a new instance of a #GObject subtype and sets its properties. Construction parameters (see #G_PARAM_CONSTRUCT, #G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.

a new instance of @object_type

the type id of the #GObject subtype to instantiate the name of the first property the value of the first property, followed optionally by more name/value pairs, followed by %NULL Creates a new instance of a #GObject subtype and sets its properties using the provided arrays. Both arrays must have exactly @n_properties elements, and the names and values correspond by index. Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.

a new instance of @object_type

the object type to instantiate the number of properties the names of each property to be set the values of each property to be set Creates a new instance of a #GObject subtype and sets its properties. Construction parameters (see #G_PARAM_CONSTRUCT, #G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.

Use g_object_new_with_properties() instead. deprecated. See #GParameter for more information.

a new instance of @object_type

the type id of the #GObject subtype to instantiate the length of the @parameters array an array of #GParameter

Find the #GParamSpec with the given name for an interface. Generally, the interface vtable passed in as @g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().

the #GParamSpec for the property of the interface with the name @property_name, or %NULL if no such property exists.

any interface vtable for the interface, or the default vtable for the interface name of a property to look up. Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property. This function is meant to be called from the interface's default vtable initialization function (the @class_init member of #GTypeInfo.) It must not be called after after @class_init has been called for any object types implementing this interface. If @pspec is a floating reference, it will be consumed.

any interface vtable for the interface, or the default vtable for the interface. the #GParamSpec for the new property Lists the properties of an interface.Generally, the interface vtable passed in as @g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().

a pointer to an array of pointers to #GParamSpec structures. The paramspecs are owned by GLib, but the array should be freed with g_free() when you are done with it.

any interface vtable for the interface, or the default vtable for the interface location to store number of properties returned.

Emits a "notify" signal for the property @property_name on @object. When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead. Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

a #GObject

Increases the reference count of the object by one and sets a callback to be called when all other references to the object are dropped, or when this is already the last reference to the object and another reference is established. This functionality is intended for binding @object to a proxy object managed by another memory manager. This is done with two paired references: the strong reference added by g_object_add_toggle_ref() and a reverse reference to the proxy object which is either a strong reference or weak reference. The setup is that when there are no other references to @object, only a weak reference is held in the reverse direction from @object to the proxy object, but when there are other references held to @object, a strong reference is held. The @notify callback is called when the reference from @object to the proxy object should be "toggled" from strong to weak (@is_last_ref true) or weak to strong (@is_last_ref false). Since a (normal) reference must be held to the object before calling g_object_add_toggle_ref(), the initial state of the reverse link is always strong. Multiple toggle references may be added to the same gobject, however if there are multiple toggle references to an object, none of them will ever be notified until all but one are removed. For this reason, you should only ever use a toggle reference if there is important state in the proxy object.

a #GObject

a function to call when this reference is the last reference to the object, or is no longer the last reference. data to pass to @notify Adds a weak reference from weak_pointer to @object to indicate that the pointer located at @weak_pointer_location is only valid during the lifetime of @object. When the @object is finalized, @weak_pointer will be set to %NULL. Note that as with g_object_weak_ref(), the weak references created by this method are not thread-safe: they cannot safely be used in one thread if the object's last g_object_unref() might happen in another thread. Use #GWeakRef if thread-safety is required.

The object that should be weak referenced.

The memory address of a pointer. Creates a binding between @source_property on @source and @target_property on @target. Whenever the @source_property is changed the @target_property is updated using the same value. For instance: |[ g_object_bind_property (action, "active", widget, "sensitive", 0); ]| Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance. If @flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual: if @target_property on @target changes then the @source_property on @source will be updated as well. The binding will automatically be removed when either the @source or the @target instances are finalized. To remove the binding without affecting the @source and the @target you can just call g_object_unref() on the returned #GBinding instance. A #GObject can have multiple bindings.

the #GBinding instance representing the binding between the two #GObject instances. The binding is released whenever the #GBinding reference count reaches zero.

the source #GObject

the property on @source to bind the target #GObject the property on @target to bind flags to pass to #GBinding Complete version of g_object_bind_property(). Creates a binding between @source_property on @source and @target_property on @target, allowing you to set the transformation functions to be used by the binding. If @flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual: if @target_property on @target changes then the @source_property on @source will be updated as well. The @transform_from function is only used in case of bidirectional bindings, otherwise it will be ignored The binding will automatically be removed when either the @source or the @target instances are finalized. This will release the reference that is being held on the #GBinding instance; if you want to hold on to the #GBinding instance, you will need to hold a reference to it. To remove the binding, call g_binding_unbind(). A #GObject can have multiple bindings. The same @user_data parameter will be used for both @transform_to and @transform_from transformation functions; the @notify function will be called once, when the binding is removed. If you need different data for each transformation function, please use g_object_bind_property_with_closures() instead.

the #GBinding instance representing the binding between the two #GObject instances. The binding is released whenever the #GBinding reference count reaches zero.

the source #GObject

the property on @source to bind the target #GObject the property on @target to bind flags to pass to #GBinding the transformation function from the @source to the @target, or %NULL to use the default the transformation function from the @target to the @source, or %NULL to use the default custom data to be passed to the transformation functions, or %NULL a function to call when disposing the binding, to free resources used by the transformation functions, or %NULL if not required Creates a binding between @source_property on @source and @target_property on @target, allowing you to set the transformation functions to be used by the binding. This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.

the #GBinding instance representing the binding between the two #GObject instances. The binding is released whenever the #GBinding reference count reaches zero.

the source #GObject

the property on @source to bind the target #GObject the property on @target to bind flags to pass to #GBinding a #GClosure wrapping the transformation function from the @source to the @target, or %NULL to use the default a #GClosure wrapping the transformation function from the @target to the @source, or %NULL to use the default A convenience function to connect multiple signals at once. The signal specs expected by this function have the form "modifier::signal_name", where modifier can be one of the following: - signal: equivalent to g_signal_connect_data (..., NULL, 0) - object-signal, object_signal: equivalent to g_signal_connect_object (..., 0) - swapped-signal, swapped_signal: equivalent to g_signal_connect_data (..., NULL, G_CONNECT_SWAPPED) - swapped_object_signal, swapped-object-signal: equivalent to g_signal_connect_object (..., G_CONNECT_SWAPPED) - signal_after, signal-after: equivalent to g_signal_connect_data (..., NULL, G_CONNECT_AFTER) - object_signal_after, object-signal-after: equivalent to g_signal_connect_object (..., G_CONNECT_AFTER) - swapped_signal_after, swapped-signal-after: equivalent to g_signal_connect_data (..., NULL, G_CONNECT_SWAPPED | G_CONNECT_AFTER) - swapped_object_signal_after, swapped-object-signal-after: equivalent to g_signal_connect_object (..., G_CONNECT_SWAPPED | G_CONNECT_AFTER) |[ menu->toplevel = g_object_connect (g_object_new (GTK_TYPE_WINDOW, "type", GTK_WINDOW_POPUP, "child", menu, NULL), "signal::event", gtk_menu_window_event, menu, "signal::size_request", gtk_menu_window_size_request, menu, "signal::destroy", gtk_widget_destroyed, &menu->toplevel, NULL); ]|

@object

a #GObject

the spec for the first signal #GCallback for the first signal, followed by data for the first signal, followed optionally by more signal spec/callback/data triples, followed by %NULL A convenience function to disconnect multiple signals at once. The signal specs expected by this function have the form "any_signal", which means to disconnect any signal with matching callback and data, or "any_signal::signal_name", which only disconnects the signal named "signal_name".

a #GObject

the spec for the first signal #GCallback for the first signal, followed by data for the first signal, followed optionally by more signal spec/callback/data triples, followed by %NULL This is a variant of g_object_get_data() which returns a 'duplicate' of the value. @dup_func defines the meaning of 'duplicate' in this context, it could e.g. take a reference on a ref-counted object. If the @key is not set on the object then @dup_func will be called with a %NULL argument. Note that @dup_func is called while user data of @object is locked. This function can be useful to avoid races when multiple threads are using object data on the same key on the same object.

the result of calling @dup_func on the value associated with @key on @object, or %NULL if not set. If @dup_func is %NULL, the value is returned unmodified.

the #GObject to store user data on

a string, naming the user data pointer function to dup the value passed as user_data to @dup_func This is a variant of g_object_get_qdata() which returns a 'duplicate' of the value. @dup_func defines the meaning of 'duplicate' in this context, it could e.g. take a reference on a ref-counted object. If the @quark is not set on the object then @dup_func will be called with a %NULL argument. Note that @dup_func is called while user data of @object is locked. This function can be useful to avoid races when multiple threads are using object data on the same key on the same object.

the result of calling @dup_func on the value associated with @quark on @object, or %NULL if not set. If @dup_func is %NULL, the value is returned unmodified.

the #GObject to store user data on

a #GQuark, naming the user data pointer function to dup the value passed as user_data to @dup_func This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().

a #GObject

Increases the freeze count on @object. If the freeze count is non-zero, the emission of "notify" signals on @object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen. This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.

a #GObject

Gets properties of an object. In general, a copy is made of the property contents and the caller is responsible for freeing the memory in the appropriate manner for the type, for instance by calling g_free() or g_object_unref(). Here is an example of using g_object_get() to get the contents of three properties: an integer, a string and an object: |[ gint intval; guint64 uint64val; gchar *strval; GObject *objval; g_object_get (my_object, "int-property", &intval, "uint64-property", &uint64val, "str-property", &strval, "obj-property", &objval, NULL); // Do something with intval, uint64val, strval, objval g_free (strval); g_object_unref (objval); ]|

a #GObject

name of the first property to get return location for the first property, followed optionally by more name/return location pairs, followed by %NULL Gets a named field from the objects table of associations (see g_object_set_data()).

the data if found, or %NULL if no such data exists.

#GObject containing the associations

name of the key for that association Gets a property of an object. The @value can be: - an empty #GValue initialized by %G_VALUE_INIT, which will be automatically initialized with the expected type of the property (since GLib 2.60) - a #GValue initialized with the expected type of the property - a #GValue initialized with a type to which the expected type of the property can be transformed In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset(). Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.

a #GObject

the name of the property to get return location for the property value This function gets back user data pointers stored via g_object_set_qdata().

The user data pointer set, or %NULL

The GObject to get a stored user data pointer from

A #GQuark, naming the user data pointer Gets properties of an object. In general, a copy is made of the property contents and the caller is responsible for freeing the memory in the appropriate manner for the type, for instance by calling g_free() or g_object_unref(). See g_object_get().

a #GObject

name of the first property to get return location for the first property, followed optionally by more name/return location pairs, followed by %NULL Gets @n_properties properties for an @object. Obtained properties will be set to @values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.

a #GObject

the number of properties the names of each property to get the values of each property to get Checks whether @object has a [floating][floating-ref] reference.

%TRUE if @object has a floating reference

a #GObject

the name of a property installed on the class of @object. Emits a "notify" signal for the property specified by @pspec on @object. This function omits the property name lookup, hence it is faster than g_object_notify(). One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.: |[ enum { PROP_0, PROP_FOO, PROP_LAST }; static GParamSpec *properties[PROP_LAST]; static void my_object_class_init (MyObjectClass *klass) { properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo", 0, 100, 50, G_PARAM_READWRITE); g_object_class_install_property (gobject_class, PROP_FOO, properties[PROP_FOO]); } ]| and then notify a change on the "foo" property with: |[ g_object_notify_by_pspec (self, properties[PROP_FOO]); ]|

a #GObject

the #GParamSpec of a property installed on the class of @object. Increases the reference count of @object. Since GLib 2.56, if `GLIB_VERSION_MAX_ALLOWED` is 2.56 or greater, the type of @object will be propagated to the return type (using the GCC typeof() extension), so any casting the caller needs to do on the return type must be explicit.

the same @object

a #GObject

Increase the reference count of @object, and possibly remove the [floating][floating-ref] reference, if @object has a floating reference. In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one. Since GLib 2.56, the type of @object will be propagated to the return type under the same conditions as for g_object_ref().

@object

a #GObject

Removes a reference added with g_object_add_toggle_ref(). The reference count of the object is decreased by one.

a #GObject

a function to call when this reference is the last reference to the object, or is no longer the last reference. data to pass to @notify Removes a weak reference from @object that was previously added using g_object_add_weak_pointer(). The @weak_pointer_location has to match the one used with g_object_add_weak_pointer().

The object that is weak referenced.

The memory address of a pointer. Compares the user data for the key @key on @object with @oldval, and if they are the same, replaces @oldval with @newval. This is like a typical atomic compare-and-exchange operation, for user data on an object. If the previous value was replaced then ownership of the old value (@oldval) is passed to the caller, including the registered destroy notify for it (passed out in @old_destroy). It’s up to the caller to free this as needed, which may or may not include using @old_destroy as sometimes replacement should not destroy the object in the normal way. See g_object_set_data() for guidance on using a small, bounded set of values for @key.

%TRUE if the existing value for @key was replaced by @newval, %FALSE otherwise.

the #GObject to store user data on

a string, naming the user data pointer the old value to compare against the new value a destroy notify for the new value destroy notify for the existing value Compares the user data for the key @quark on @object with @oldval, and if they are the same, replaces @oldval with @newval. This is like a typical atomic compare-and-exchange operation, for user data on an object. If the previous value was replaced then ownership of the old value (@oldval) is passed to the caller, including the registered destroy notify for it (passed out in @old_destroy). It’s up to the caller to free this as needed, which may or may not include using @old_destroy as sometimes replacement should not destroy the object in the normal way.

%TRUE if the existing value for @quark was replaced by @newval, %FALSE otherwise.

the #GObject to store user data on

a #GQuark, naming the user data pointer the old value to compare against the new value a destroy notify for the new value destroy notify for the existing value Releases all references to other objects. This can be used to break reference cycles. This function should only be called from object system implementations.

a #GObject

Sets properties on an object. The same caveats about passing integer literals as varargs apply as with g_object_new(). In particular, any integer literals set as the values for properties of type #gint64 or #guint64 must be 64 bits wide, using the %G_GINT64_CONSTANT or %G_GUINT64_CONSTANT macros. Note that the "notify" signals are queued and only emitted (in reverse order) after all properties have been set. See g_object_freeze_notify().

a #GObject

name of the first property to set value for the first property, followed optionally by more name/value pairs, followed by %NULL Each object carries around a table of associations from strings to pointers. This function lets you set an association. If the object already had an association with that name, the old association will be destroyed. Internally, the @key is converted to a #GQuark using g_quark_from_string(). This means a copy of @key is kept permanently (even after @object has been finalized) — so it is recommended to only use a small, bounded set of values for @key in your program, to avoid the #GQuark storage growing unbounded.

#GObject containing the associations.

name of the key data to associate with that key Like g_object_set_data() except it adds notification for when the association is destroyed, either by setting it to a different value or when the object is destroyed. Note that the @destroy callback is not called if @data is %NULL.

#GObject containing the associations

name of the key data to associate with that key function to call when the association is destroyed Sets a property on an object.

a #GObject

the name of the property to set the value This sets an opaque, named pointer on an object. The name is specified through a #GQuark (retrieved e.g. via g_quark_from_static_string()), and the pointer can be gotten back from the @object with g_object_get_qdata() until the @object is finalized. Setting a previously set user data pointer, overrides (frees) the old pointer set, using #NULL as pointer essentially removes the data stored.

The GObject to set store a user data pointer

A #GQuark, naming the user data pointer An opaque user data pointer This function works like g_object_set_qdata(), but in addition, a void (*destroy) (gpointer) function may be specified which is called with @data as argument when the @object is finalized, or the data is being overwritten by a call to g_object_set_qdata() with the same @quark.

The GObject to set store a user data pointer

A #GQuark, naming the user data pointer An opaque user data pointer Function to invoke with @data as argument, when @data needs to be freed Sets properties on an object.

a #GObject

name of the first property to set value for the first property, followed optionally by more name/value pairs, followed by %NULL Sets @n_properties properties for an @object. Properties to be set will be taken from @values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.

a #GObject

the number of properties the names of each property to be set the values of each property to be set Remove a specified datum from the object's data associations, without invoking the association's destroy handler.

the data if found, or %NULL if no such data exists.

#GObject containing the associations

name of the key This function gets back user data pointers stored via g_object_set_qdata() and removes the @data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example: |[ void object_add_to_user_list (GObject *object, const gchar *new_string) { // the quark, naming the object data GQuark quark_string_list = g_quark_from_static_string ("my-string-list"); // retrieve the old string list GList *list = g_object_steal_qdata (object, quark_string_list); // prepend new string list = g_list_prepend (list, g_strdup (new_string)); // this changed 'list', so we need to set it again g_object_set_qdata_full (object, quark_string_list, list, free_string_list); } static void free_string_list (gpointer data) { GList *node, *list = data; for (node = list; node; node = node->next) g_free (node->data); g_list_free (list); } ]| Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().

The user data pointer set, or %NULL

The GObject to get a stored user data pointer from

A #GQuark, naming the user data pointer Reverts the effect of a previous call to g_object_freeze_notify(). The freeze count is decreased on @object and when it reaches zero, queued "notify" signals are emitted. Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued. It is an error to call this function when the freeze count is zero.

a #GObject

Decreases the reference count of @object. When its reference count drops to 0, the object is finalized (i.e. its memory is freed). If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.

a #GObject

This function essentially limits the life time of the @closure to the life time of the object. That is, when the object is finalized, the @closure is invalidated by calling g_closure_invalidate() on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, g_object_ref() and g_object_unref() are added as marshal guards to the @closure, to ensure that an extra reference count is held on @object during invocation of the @closure. Usually, this function will be called on closures that use this @object as closure data.

#GObject restricting lifetime of @closure

#GClosure to watch Adds a weak reference callback to an object. Weak references are used for notification when an object is finalized. They are called "weak references" because they allow you to safely hold a pointer to an object without calling g_object_ref() (g_object_ref() adds a strong reference, that is, forces the object to stay alive). Note that the weak references created by this method are not thread-safe: they cannot safely be used in one thread if the object's last g_object_unref() might happen in another thread. Use #GWeakRef if thread-safety is required.

#GObject to reference weakly

callback to invoke before the object is freed extra data to pass to notify Removes a weak reference callback to an object.

#GObject to remove a weak reference from

callback to search for data to search for The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al. Note that getting this signal doesn’t itself guarantee that the value of the property has actually changed. When it is emitted is determined by the derived GObject class. If the implementor did not create the property with %G_PARAM_EXPLICIT_NOTIFY, then any call to g_object_set_property() results in ::notify being emitted, even if the new value is the same as the old. If they did pass %G_PARAM_EXPLICIT_NOTIFY, then this signal is emitted only when they explicitly call g_object_notify() or g_object_notify_by_pspec(), and common practice is to do that only when the value has actually changed. This signal is typically used to obtain change notification for a single property, by specifying the property name as a detail in the g_signal_connect() call, like this: |[ g_signal_connect (text_view->buffer, "notify::paste-target-list", G_CALLBACK (gtk_text_view_target_list_notify), text_view) ]| It is important to note that you must use [canonical parameter names][canonical-parameter-names] as detail strings for the notify signal.

the #GParamSpec of the property which changed. The class structure for the GObject type. |[ // Example of implementing a singleton using a constructor. static MySingleton *the_singleton = NULL; static GObject* my_singleton_constructor (GType type, guint n_construct_params, GObjectConstructParam *construct_params) { GObject *object; if (!the_singleton) { object = G_OBJECT_CLASS (parent_class)->constructor (type, n_construct_params, construct_params); the_singleton = MY_SINGLETON (object); } else object = g_object_ref (G_OBJECT (the_singleton)); return object; } ]| the parent class

a #GObject

Looks up the #GParamSpec for a property of a class.

the #GParamSpec for the property, or %NULL if the class doesn't have a property of that name

a #GObjectClass

the name of the property to look up Installs new properties from an array of #GParamSpecs. All properties should be installed during the class initializer. It is possible to install properties after that, but doing so is not recommend, and specifically, is not guaranteed to be thread-safe vs. use of properties on the same type on other threads. The property id of each property is the index of each #GParamSpec in the @pspecs array. The property id of 0 is treated specially by #GObject and it should not be used to store a #GParamSpec. This function should be used if you plan to use a static array of #GParamSpecs and g_object_notify_by_pspec(). For instance, this class initialization: |[ enum { PROP_0, PROP_FOO, PROP_BAR, N_PROPERTIES }; static GParamSpec *obj_properties[N_PROPERTIES] = { NULL, }; static void my_object_class_init (MyObjectClass *klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); obj_properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "Foo", -1, G_MAXINT, 0, G_PARAM_READWRITE); obj_properties[PROP_BAR] = g_param_spec_string ("bar", "Bar", "Bar", NULL, G_PARAM_READWRITE); gobject_class->set_property = my_object_set_property; gobject_class->get_property = my_object_get_property; g_object_class_install_properties (gobject_class, N_PROPERTIES, obj_properties); } ]| allows calling g_object_notify_by_pspec() to notify of property changes: |[ void my_object_set_foo (MyObject *self, gint foo) { if (self->foo != foo) { self->foo = foo; g_object_notify_by_pspec (G_OBJECT (self), obj_properties[PROP_FOO]); } } ]|

a #GObjectClass

the length of the #GParamSpecs array the #GParamSpecs array defining the new properties Installs a new property. All properties should be installed during the class initializer. It is possible to install properties after that, but doing so is not recommend, and specifically, is not guaranteed to be thread-safe vs. use of properties on the same type on other threads. Note that it is possible to redefine a property in a derived class, by installing a property with the same name. This can be useful at times, e.g. to change the range of allowed values or the default value.

a #GObjectClass

the id for the new property the #GParamSpec for the new property Get an array of #GParamSpec* for all properties of a class.

an array of #GParamSpec* which should be freed after use

a #GObjectClass

return location for the length of the returned array Registers @property_id as referring to a property with the name @name in a parent class or in an interface implemented by @oclass. This allows this class to "override" a property implementation in a parent class or to provide the implementation of a property from an interface. Internally, overriding is implemented by creating a property of type #GParamSpecOverride; generally operations that query the properties of the object class, such as g_object_class_find_property() or g_object_class_list_properties() will return the overridden property. However, in one case, the @construct_properties argument of the @constructor virtual function, the #GParamSpecOverride is passed instead, so that the @param_id field of the #GParamSpec will be correct. For virtually all uses, this makes no difference. If you need to get the overridden property, you can call g_param_spec_get_redirect_target().

a #GObjectClass

the new property ID the name of a property registered in a parent class or in an interface of this class. The GObjectConstructParam struct is an auxiliary structure used to hand #GParamSpec/#GValue pairs to the @constructor of a #GObjectClass. the #GParamSpec of the construct parameter the value to set the parameter to The type of the @finalize function of #GObjectClass.

the #GObject being finalized The type of the @get_property function of #GObjectClass.

a #GObject the numeric id under which the property was registered with g_object_class_install_property(). a #GValue to return the property value in the #GParamSpec describing the property The type of the @set_property function of #GObjectClass.

a #GObject the numeric id under which the property was registered with g_object_class_install_property(). the new value for the property the #GParamSpec describing the property Mask containing the bits of #GParamSpec.flags which are reserved for GLib.

Casts a derived #GParamSpec object (e.g. of type #GParamSpecInt) into a #GParamSpec object. a valid #GParamSpec

Cast a #GParamSpec instance into a #GParamSpecBoolean. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecBoxed. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecChar. a valid #GParamSpec instance

Casts a derived #GParamSpecClass structure into a #GParamSpecClass structure. a valid #GParamSpecClass

Cast a #GParamSpec instance into a #GParamSpecDouble. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecEnum. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecFlags. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecFloat. a valid #GParamSpec instance

Retrieves the #GParamSpecClass of a #GParamSpec. a valid #GParamSpec

Casts a #GParamSpec into a #GParamSpecGType. a #GParamSpec

Cast a #GParamSpec instance into a #GParamSpecInt. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecInt64. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecLong. a valid #GParamSpec instance

Casts a #GParamSpec instance into a #GParamSpecObject. a valid #GParamSpec instance

Casts a #GParamSpec into a #GParamSpecOverride. a #GParamSpec

Casts a #GParamSpec instance into a #GParamSpecParam. a valid #GParamSpec instance

Casts a #GParamSpec instance into a #GParamSpecPointer. a valid #GParamSpec instance

Casts a #GParamSpec instance into a #GParamSpecString. a valid #GParamSpec instance

Retrieves the #GType of this @pspec. a valid #GParamSpec

Retrieves the #GType name of this @pspec. a valid #GParamSpec

Cast a #GParamSpec instance into a #GParamSpecUChar. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecUInt. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecUInt64. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecULong. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecUnichar. a valid #GParamSpec instance

Cast a #GParamSpec instance into a #GParamSpecValueArray.

Use #GArray instead of #GValueArray

a valid #GParamSpec instance

Retrieves the #GType to initialize a #GValue for this parameter. a valid #GParamSpec

Casts a #GParamSpec into a #GParamSpecVariant. a #GParamSpec

#GParamFlags value alias for %G_PARAM_STATIC_NAME | %G_PARAM_STATIC_NICK | %G_PARAM_STATIC_BLURB. Since 2.13.0 Minimum shift count to be used for user defined flags, to be stored in #GParamSpec.flags. The maximum allowed is 10.

Evaluates to the @field_name inside the @inst private data structure for @TypeName. Note that this macro can only be used together with the G_DEFINE_TYPE_* and G_ADD_PRIVATE() macros, since it depends on variable names from those macros. the name of the type in CamelCase the instance of @TypeName you wish to access the type of the field in the private data structure the name of the field in the private data structure

Evaluates to a pointer to the @field_name inside the @inst private data structure for @TypeName. Note that this macro can only be used together with the G_DEFINE_TYPE_* and G_ADD_PRIVATE() macros, since it depends on variable names from those macros. the name of the type in CamelCase the instance of @TypeName you wish to access the name of the field in the private data structure

Evaluates to the offset of the @field inside the instance private data structure for @TypeName. Note that this macro can only be used together with the G_DEFINE_TYPE_* and G_ADD_PRIVATE() macros, since it depends on variable names from those macros. the name of the type in CamelCase the name of the field in the private data structure

Through the #GParamFlags flag values, certain aspects of parameters can be configured. See also #G_PARAM_STATIC_STRINGS. the parameter is readable the parameter is writable alias for %G_PARAM_READABLE | %G_PARAM_WRITABLE the parameter will be set upon object construction the parameter can only be set upon object construction upon parameter conversion (see g_param_value_convert()) strict validation is not required the string used as name when constructing the parameter is guaranteed to remain valid and unmodified for the lifetime of the parameter. Since 2.8 internal the string used as nick when constructing the parameter is guaranteed to remain valid and unmmodified for the lifetime of the parameter. Since 2.8 the string used as blurb when constructing the parameter is guaranteed to remain valid and unmodified for the lifetime of the parameter. Since 2.8 calls to g_object_set_property() for this property will not automatically result in a "notify" signal being emitted: the implementation must call g_object_notify() themselves in case the property actually changes. Since: 2.42. the parameter is deprecated and will be removed in a future version. A warning will be generated if it is used while running with G_ENABLE_DIAGNOSTIC=1. Since 2.26 #GParamSpec is an object structure that encapsulates the metadata required to specify parameters, such as e.g. #GObject properties. ## Parameter names # {#canonical-parameter-names} A property name consists of one or more segments consisting of ASCII letters and digits, separated by either the `-` or `_` character. The first character of a property name must be a letter. These are the same rules as for signal naming (see g_signal_new()). When creating and looking up a #GParamSpec, either separator can be used, but they cannot be mixed. Using `-` is considerably more efficient, and is the ‘canonical form’. Using `_` is discouraged. Creates a new #GParamSpec instance. See [canonical parameter names][canonical-parameter-names] for details of the rules for @name. Names which violate these rules lead to undefined behaviour. Beyond the name, #GParamSpecs have two more descriptive strings associated with them, the @nick, which should be suitable for use as a label for the property in a property editor, and the @blurb, which should be a somewhat longer description, suitable for e.g. a tooltip. The @nick and @blurb should ideally be localized.

a newly allocated #GParamSpec instance

the #GType for the property; must be derived from #G_TYPE_PARAM the canonical name of the property the nickname of the property a short description of the property a combination of #GParamFlags Validate a property name for a #GParamSpec. This can be useful for dynamically-generated properties which need to be validated at run-time before actually trying to create them. See [canonical parameter names][canonical-parameter-names] for details of the rules for valid names.

%TRUE if @name is a valid property name, %FALSE otherwise.

the canonical name of the property

Get the short description of a #GParamSpec.

the short description of @pspec.

a valid #GParamSpec

Gets the default value of @pspec as a pointer to a #GValue. The #GValue will remain valid for the life of @pspec.

a pointer to a #GValue which must not be modified

a #GParamSpec

Get the name of a #GParamSpec. The name is always an "interned" string (as per g_intern_string()). This allows for pointer-value comparisons.

the name of @pspec.

a valid #GParamSpec

Gets the GQuark for the name.

the GQuark for @pspec->name.

a #GParamSpec

Get the nickname of a #GParamSpec.

the nickname of @pspec.

a valid #GParamSpec

Gets back user data pointers stored via g_param_spec_set_qdata().

the user data pointer set, or %NULL

a valid #GParamSpec

a #GQuark, naming the user data pointer If the paramspec redirects operations to another paramspec, returns that paramspec. Redirect is used typically for providing a new implementation of a property in a derived type while preserving all the properties from the parent type. Redirection is established by creating a property of type #GParamSpecOverride. See g_object_class_override_property() for an example of the use of this capability.

paramspec to which requests on this paramspec should be redirected, or %NULL if none.

a #GParamSpec

Increments the reference count of @pspec.

the #GParamSpec that was passed into this function

a valid #GParamSpec

Convenience function to ref and sink a #GParamSpec.

the #GParamSpec that was passed into this function

a valid #GParamSpec

Sets an opaque, named pointer on a #GParamSpec. The name is specified through a #GQuark (retrieved e.g. via g_quark_from_static_string()), and the pointer can be gotten back from the @pspec with g_param_spec_get_qdata(). Setting a previously set user data pointer, overrides (frees) the old pointer set, using %NULL as pointer essentially removes the data stored.

the #GParamSpec to set store a user data pointer

a #GQuark, naming the user data pointer an opaque user data pointer This function works like g_param_spec_set_qdata(), but in addition, a `void (*destroy) (gpointer)` function may be specified which is called with @data as argument when the @pspec is finalized, or the data is being overwritten by a call to g_param_spec_set_qdata() with the same @quark.

the #GParamSpec to set store a user data pointer

a #GQuark, naming the user data pointer an opaque user data pointer function to invoke with @data as argument, when @data needs to be freed The initial reference count of a newly created #GParamSpec is 1, even though no one has explicitly called g_param_spec_ref() on it yet. So the initial reference count is flagged as "floating", until someone calls `g_param_spec_ref (pspec); g_param_spec_sink (pspec);` in sequence on it, taking over the initial reference count (thus ending up with a @pspec that has a reference count of 1 still, but is not flagged "floating" anymore).

a valid #GParamSpec

Gets back user data pointers stored via g_param_spec_set_qdata() and removes the @data from @pspec without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier.

the user data pointer set, or %NULL

the #GParamSpec to get a stored user data pointer from

a #GQuark, naming the user data pointer Decrements the reference count of a @pspec.

a valid #GParamSpec

private #GTypeInstance portion name of this parameter: always an interned string #GParamFlags flags for this parameter the #GValue type for this parameter #GType type that uses (introduces) this parameter A #GParamSpec derived structure that contains the meta data for boolean properties. private #GParamSpec portion default value for the property specified A #GParamSpec derived structure that contains the meta data for boxed properties. private #GParamSpec portion A #GParamSpec derived structure that contains the meta data for character properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified The class structure for the GParamSpec type. Normally, GParamSpec classes are filled by g_param_type_register_static(). the parent class the #GValue type for this parameter

A #GParamSpec derived structure that contains the meta data for double properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified values closer than @epsilon will be considered identical by g_param_values_cmp(); the default value is 1e-90. A #GParamSpec derived structure that contains the meta data for enum properties. private #GParamSpec portion the #GEnumClass for the enum default value for the property specified A #GParamSpec derived structure that contains the meta data for flags properties. private #GParamSpec portion the #GFlagsClass for the flags default value for the property specified A #GParamSpec derived structure that contains the meta data for float properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified values closer than @epsilon will be considered identical by g_param_values_cmp(); the default value is 1e-30. A #GParamSpec derived structure that contains the meta data for #GType properties. private #GParamSpec portion a #GType whose subtypes can occur as values A #GParamSpec derived structure that contains the meta data for integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for 64bit integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for long integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for object properties. private #GParamSpec portion This is a type of #GParamSpec type that simply redirects operations to another paramspec. All operations other than getting or setting the value are redirected, including accessing the nick and blurb, validating a value, and so forth. See g_param_spec_get_redirect_target() for retrieving the overridden property. #GParamSpecOverride is used in implementing g_object_class_override_property(), and will not be directly useful unless you are implementing a new base type similar to GObject. A #GParamSpec derived structure that contains the meta data for %G_TYPE_PARAM properties. private #GParamSpec portion A #GParamSpec derived structure that contains the meta data for pointer properties. private #GParamSpec portion A #GParamSpecPool maintains a collection of #GParamSpecs which can be quickly accessed by owner and name. The implementation of the #GObject property system uses such a pool to store the #GParamSpecs of the properties all object types. Inserts a #GParamSpec in the pool.

a #GParamSpecPool.

the #GParamSpec to insert a #GType identifying the owner of @pspec Gets an array of all #GParamSpecs owned by @owner_type in the pool.

a newly allocated array containing pointers to all #GParamSpecs owned by @owner_type in the pool

a #GParamSpecPool

the owner to look for return location for the length of the returned array Gets an #GList of all #GParamSpecs owned by @owner_type in the pool.

a #GList of all #GParamSpecs owned by @owner_type in the pool#GParamSpecs.

a #GParamSpecPool

the owner to look for Looks up a #GParamSpec in the pool.

The found #GParamSpec, or %NULL if no matching #GParamSpec was found.

a #GParamSpecPool

the name to look for the owner to look for If %TRUE, also try to find a #GParamSpec with @param_name owned by an ancestor of @owner_type. Removes a #GParamSpec from the pool.

a #GParamSpecPool

the #GParamSpec to remove Creates a new #GParamSpecPool. If @type_prefixing is %TRUE, lookups in the newly created pool will allow to specify the owner as a colon-separated prefix of the property name, like "GtkContainer:border-width". This feature is deprecated, so you should always set @type_prefixing to %FALSE.

a newly allocated #GParamSpecPool.

Whether the pool will support type-prefixed property names. A #GParamSpec derived structure that contains the meta data for string properties. private #GParamSpec portion default value for the property specified a string containing the allowed values for the first byte a string containing the allowed values for the subsequent bytes the replacement byte for bytes which don't match @cset_first or @cset_nth. replace empty string by %NULL replace %NULL strings by an empty string This structure is used to provide the type system with the information required to initialize and destruct (finalize) a parameter's class and instances thereof. The initialized structure is passed to the g_param_type_register_static() The type system will perform a deep copy of this structure, so its memory does not need to be persistent across invocation of g_param_type_register_static(). Size of the instance (object) structure. Prior to GLib 2.10, it specified the number of pre-allocated (cached) instances to reserve memory for (0 indicates no caching). Since GLib 2.10, it is ignored, since instances are allocated with the [slice allocator][glib-Memory-Slices] now.

The #GType of values conforming to this #GParamSpec

A #GParamSpec derived structure that contains the meta data for unsigned character properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for unsigned integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for unsigned 64bit integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for unsigned long integer properties. private #GParamSpec portion minimum value for the property specified maximum value for the property specified default value for the property specified A #GParamSpec derived structure that contains the meta data for unichar (unsigned integer) properties. private #GParamSpec portion default value for the property specified A #GParamSpec derived structure that contains the meta data for #GValueArray properties. private #GParamSpec portion a #GParamSpec describing the elements contained in arrays of this property, may be %NULL if greater than 0, arrays of this property will always have this many elements A #GParamSpec derived structure that contains the meta data for #GVariant properties. When comparing values with g_param_values_cmp(), scalar values with the same type will be compared with g_variant_compare(). Other non-%NULL variants will be checked for equality with g_variant_equal(), and their sort order is otherwise undefined. %NULL is ordered before non-%NULL variants. Two %NULL values compare equal. private #GParamSpec portion a #GVariantType, or %NULL a #GVariant, or %NULL The GParameter struct is an auxiliary structure used to hand parameter name/value pairs to g_object_newv().

This type is not introspectable.

the parameter name the parameter value A mask for all #GSignalFlags bits. A mask for all #GSignalMatchType bits. The signal accumulator is a special callback function that can be used to collect return values of the various callbacks that are called during a signal emission. The signal accumulator is specified at signal creation time, if it is left %NULL, no accumulation of callback return values is performed. The return value of signal emissions is then the value returned by the last callback.

The accumulator function returns whether the signal emission should be aborted. Returning %FALSE means to abort the current emission and %TRUE is returned for continuation.

Signal invocation hint, see #GSignalInvocationHint. Accumulator to collect callback return values in, this is the return value of the current signal emission. A #GValue holding the return value of the signal handler. Callback data that was specified when creating the signal. A simple function pointer to get invoked when the signal is emitted. This allows you to tie a hook to the signal type, so that it will trap all emissions of that signal, from any object. You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag.

whether it wants to stay connected. If it returns %FALSE, the signal hook is disconnected (and destroyed).

Signal invocation hint, see #GSignalInvocationHint. the number of parameters to the function, including the instance on which the signal was emitted. the instance on which the signal was emitted, followed by the parameters of the emission. user data associated with the hook. The signal flags are used to specify a signal's behaviour, the overall signal description outlines how especially the RUN flags control the stages of a signal emission. Invoke the object method handler in the first emission stage. Invoke the object method handler in the third emission stage. Invoke the object method handler in the last emission stage. Signals being emitted for an object while currently being in emission for this very object will not be emitted recursively, but instead cause the first emission to be restarted. This signal supports "::detail" appendices to the signal name upon handler connections and emissions. Action signals are signals that may freely be emitted on alive objects from user code via g_signal_emit() and friends, without the need of being embedded into extra code that performs pre or post emission adjustments on the object. They can also be thought of as object methods which can be called generically by third-party code. No emissions hooks are supported for this signal. Varargs signal emission will always collect the arguments, even if there are no signal handlers connected. Since 2.30. The signal is deprecated and will be removed in a future version. A warning will be generated if it is connected while running with G_ENABLE_DIAGNOSTIC=1. Since 2.32. The #GSignalInvocationHint structure is used to pass on additional information to callbacks during a signal emission. The signal id of the signal invoking the callback The detail passed on for this emission The stage the signal emission is currently in, this field will contain one of %G_SIGNAL_RUN_FIRST, %G_SIGNAL_RUN_LAST or %G_SIGNAL_RUN_CLEANUP. The match types specify what g_signal_handlers_block_matched(), g_signal_handlers_unblock_matched() and g_signal_handlers_disconnect_matched() match signals by. The signal id must be equal. The signal detail must be equal. The closure must be the same. The C closure callback must be the same. The closure data must be the same. Only unblocked signals may be matched. A structure holding in-depth information for a specific signal. It is filled in by the g_signal_query() function. The signal id of the signal being queried, or 0 if the signal to be queried was unknown. The signal name. The interface/instance type that this signal can be emitted for. The signal flags as passed in to g_signal_new(). The return type for user callbacks. The number of parameters that user callbacks take. The individual parameter types for user callbacks, note that the effective callback signature is: |[ @return_type callback (#gpointer data1, [param_types param_names,] gpointer data2); ]|

Checks that @g_class is a class structure of the type identified by @g_type and issues a warning if this is not the case. Returns @g_class casted to a pointer to @c_type. %NULL is not a valid class structure. This macro should only be used in type implementations. Location of a #GTypeClass structure The type to be returned The corresponding C type of class structure of @g_type

Checks if @g_class is a class structure of the type identified by @g_type. If @g_class is %NULL, %FALSE will be returned. This macro should only be used in type implementations. Location of a #GTypeClass structure The type to be checked

Checks if @instance is a valid #GTypeInstance structure, otherwise issues a warning and returns %FALSE. %NULL is not a valid #GTypeInstance. This macro should only be used in type implementations. Location of a #GTypeInstance structure

Checks that @instance is an instance of the type identified by @g_type and issues a warning if this is not the case. Returns @instance casted to a pointer to @c_type. No warning will be issued if @instance is %NULL, and %NULL will be returned. This macro should only be used in type implementations. Location of a #GTypeInstance structure The type to be returned The corresponding C type of @g_type

Checks if @instance is an instance of the fundamental type identified by @g_type. If @instance is %NULL, %FALSE will be returned. This macro should only be used in type implementations. Location of a #GTypeInstance structure. The fundamental type to be checked

Checks if @instance is an instance of the type identified by @g_type. If @instance is %NULL, %FALSE will be returned. This macro should only be used in type implementations. Location of a #GTypeInstance structure. The type to be checked

Checks if @value has been initialized to hold values of a value type. This macro should only be used in type implementations. a #GValue

Checks if @value has been initialized to hold values of type @g_type. This macro should only be used in type implementations. a #GValue The type to be checked

Gets the private class structure for a particular type. The private structure must have been registered in the get_type() function with g_type_add_class_private(). This macro should only be used in type implementations. the class of a type deriving from @private_type the type identifying which private data to retrieve The C type for the private structure

A bit in the type number that's supposed to be left untouched.

Get the type identifier from a given @class structure. This macro should only be used in type implementations. Location of a valid #GTypeClass structure

Get the type identifier from a given @instance structure. This macro should only be used in type implementations. Location of a valid #GTypeInstance structure

Get the type identifier from a given @interface structure. This macro should only be used in type implementations. Location of a valid #GTypeInterface structure

The fundamental type which is the ancestor of @type. Fundamental types are types that serve as ultimate bases for the derived types, thus they are the roots of distinct inheritance hierarchies. A #GType value.

An integer constant that represents the number of identifiers reserved for types that are assigned at compile-time. Shift value used in converting numbers to type IDs.

Checks if @type has a #GTypeValueTable. A #GType value

Get the class structure of a given @instance, casted to a specified ancestor type @g_type of the instance. Note that while calling a GInstanceInitFunc(), the class pointer gets modified, so it might not always return the expected pointer. This macro should only be used in type implementations. Location of the #GTypeInstance structure The #GType of the class to be returned The C type of the class structure

Get the interface structure for interface @g_type of a given @instance. This macro should only be used in type implementations. Location of the #GTypeInstance structure The #GType of the interface to be returned The C type of the interface structure

Gets the private structure for a particular type. The private structure must have been registered in the class_init function with g_type_class_add_private(). This macro should only be used in type implementations.

Use %G_ADD_PRIVATE and the generated `your_type_get_instance_private()` function instead

the instance of a type deriving from @private_type the type identifying which private data to retrieve The C type for the private structure

Checks if @type is an abstract type. An abstract type cannot be instantiated and is normally used as an abstract base class for derived classes. A #GType value

Checks if @type is a classed type. A #GType value

Checks if @type is a deep derivable type. A deep derivable type can be used as the base class of a deep (multi-level) class hierarchy. A #GType value

Checks if @type is a derivable type. A derivable type can be used as the base class of a flat (single-level) class hierarchy. A #GType value

Checks if @type is derived (or in object-oriented terminology: inherited) from another type (this holds true for all non-fundamental types). A #GType value

Checks whether @type "is a" %G_TYPE_ENUM. a #GType ID.

Checks whether @type "is a" %G_TYPE_FLAGS. a #GType ID.

Checks if @type is a fundamental type. A #GType value

Checks if @type can be instantiated. Instantiation is the process of creating an instance (object) of this type. A #GType value

Checks if @type is an interface type. An interface type provides a pure API, the implementation of which is provided by another type (which is then said to conform to the interface). GLib interfaces are somewhat analogous to Java interfaces and C++ classes containing only pure virtual functions, with the difference that GType interfaces are not derivable (but see g_type_interface_add_prerequisite() for an alternative). A #GType value

Check if the passed in type id is a %G_TYPE_OBJECT or derived from it. Type id to check

Checks whether @type "is a" %G_TYPE_PARAM. a #GType ID

Checks whether the passed in type ID can be used for g_value_init(). That is, this macro checks whether this type provides an implementation of the #GTypeValueTable functions required for a type to create a #GValue of. A #GType value.

Checks if @type is an abstract value type. An abstract value type introduces a value table, but can't be used for g_value_init() and is normally used as an abstract base type for derived value types. A #GType value

Checks if @type is a value type and can be used with g_value_init(). A #GType value

Get the type ID for the fundamental type number @x. Use g_type_fundamental_next() instead of this macro to create new fundamental types. the fundamental type number.

First fundamental type number to create a new fundamental type id with G_TYPE_MAKE_FUNDAMENTAL() reserved for BSE. Last fundamental type number reserved for BSE. First fundamental type number to create a new fundamental type id with G_TYPE_MAKE_FUNDAMENTAL() reserved for GLib. Last fundamental type number reserved for GLib. First available fundamental type number to create new fundamental type id with G_TYPE_MAKE_FUNDAMENTAL(). A callback function used for notification when the state of a toggle reference changes. See g_object_add_toggle_ref().

Callback data passed to g_object_add_toggle_ref() The object on which g_object_add_toggle_ref() was called. %TRUE if the toggle reference is now the last reference to the object. %FALSE if the toggle reference was the last reference and there are now other references. An opaque structure used as the base of all classes. Registers a private structure for an instantiatable type. When an object is allocated, the private structures for the type and all of its parent types are allocated sequentially in the same memory block as the public structures, and are zero-filled. Note that the accumulated size of the private structures of a type and all its parent types cannot exceed 64 KiB. This function should be called in the type's class_init() function. The private structure can be retrieved using the G_TYPE_INSTANCE_GET_PRIVATE() macro. The following example shows attaching a private structure MyObjectPrivate to an object MyObject defined in the standard GObject fashion in the type's class_init() function. Note the use of a structure member "priv" to avoid the overhead of repeatedly calling MY_OBJECT_GET_PRIVATE(). |[ typedef struct _MyObject MyObject; typedef struct _MyObjectPrivate MyObjectPrivate; struct _MyObject { GObject parent; MyObjectPrivate *priv; }; struct _MyObjectPrivate { int some_field; }; static void my_object_class_init (MyObjectClass *klass) { g_type_class_add_private (klass, sizeof (MyObjectPrivate)); } static void my_object_init (MyObject *my_object) { my_object->priv = G_TYPE_INSTANCE_GET_PRIVATE (my_object, MY_TYPE_OBJECT, MyObjectPrivate); // my_object->priv->some_field will be automatically initialised to 0 } static int my_object_get_some_field (MyObject *my_object) { MyObjectPrivate *priv; g_return_val_if_fail (MY_IS_OBJECT (my_object), 0); priv = my_object->priv; return priv->some_field; } ]|

Use the G_ADD_PRIVATE() macro with the `G_DEFINE_*` family of macros to add instance private data to a type

class structure for an instantiatable type

size of private structure Gets the offset of the private data for instances of @g_class. This is how many bytes you should add to the instance pointer of a class in order to get the private data for the type represented by @g_class. You can only call this function after you have registered a private data area for @g_class using g_type_class_add_private().

the offset, in bytes

a #GTypeClass

This is a convenience function often needed in class initializers. It returns the class structure of the immediate parent type of the class passed in. Since derived classes hold a reference count on their parent classes as long as they are instantiated, the returned class will always exist. This function is essentially equivalent to: g_type_class_peek (g_type_parent (G_TYPE_FROM_CLASS (g_class)))

the parent class of @g_class

the #GTypeClass structure to retrieve the parent class for

Decrements the reference count of the class structure being passed in. Once the last reference count of a class has been released, classes may be finalized by the type system, so further dereferencing of a class pointer after g_type_class_unref() are invalid.

a #GTypeClass structure to unref

A variant of g_type_class_unref() for use in #GTypeClassCacheFunc implementations. It unreferences a class without consulting the chain of #GTypeClassCacheFuncs, avoiding the recursion which would occur otherwise.

a #GTypeClass structure to unref

This function is essentially the same as g_type_class_ref(), except that the classes reference count isn't incremented. As a consequence, this function may return %NULL if the class of the type passed in does not currently exist (hasn't been referenced before).

the #GTypeClass structure for the given type ID or %NULL if the class does not currently exist

type ID of a classed type A more efficient version of g_type_class_peek() which works only for static types.

the #GTypeClass structure for the given type ID or %NULL if the class does not currently exist or is dynamically loaded

type ID of a classed type Increments the reference count of the class structure belonging to @type. This function will demand-create the class if it doesn't exist already.

the #GTypeClass structure for the given type ID

type ID of a classed type A callback function which is called when the reference count of a class drops to zero. It may use g_type_class_ref() to prevent the class from being freed. You should not call g_type_class_unref() from a #GTypeClassCacheFunc function to prevent infinite recursion, use g_type_class_unref_uncached() instead. The functions have to check the class id passed in to figure whether they actually want to cache the class of this type, since all classes are routed through the same #GTypeClassCacheFunc chain.

%TRUE to stop further #GTypeClassCacheFuncs from being called, %FALSE to continue

data that was given to the g_type_add_class_cache_func() call The #GTypeClass structure which is unreferenced These flags used to be passed to g_type_init_with_debug_flags() which is now deprecated. If you need to enable debugging features, use the GOBJECT_DEBUG environment variable.

g_type_init() is now done automatically

Print no messages Print messages about object bookkeeping Print messages about signal emissions Keep a count of instances of each type Mask covering all debug flags Bit masks used to check or determine characteristics of a type. Indicates an abstract type. No instances can be created for an abstract type Indicates an abstract value type, i.e. a type that introduces a value table, but can't be used for g_value_init() Bit masks used to check or determine specific characteristics of a fundamental type. Indicates a classed type Indicates an instantiable type (implies classed) Indicates a flat derivable type Indicates a deep derivable type (implies derivable) A structure that provides information to the type system which is used specifically for managing fundamental types. #GTypeFundamentalFlags describing the characteristics of the fundamental type This structure is used to provide the type system with the information required to initialize and destruct (finalize) a type's class and its instances. The initialized structure is passed to the g_type_register_static() function (or is copied into the provided #GTypeInfo structure in the g_type_plugin_complete_type_info()). The type system will perform a deep copy of this structure, so its memory does not need to be persistent across invocation of g_type_register_static(). Size of the class structure (required for interface, classed and instantiatable types) Location of the base initialization function (optional) Location of the base finalization function (optional) Location of the class initialization function for classed and instantiatable types. Location of the default vtable inititalization function for interface types. (optional) This function is used both to fill in virtual functions in the class or default vtable, and to do type-specific setup such as registering signals and object properties. Location of the class finalization function for classed and instantiatable types. Location of the default vtable finalization function for interface types. (optional) User-supplied data passed to the class init/finalize functions Size of the instance (object) structure (required for instantiatable types only) Prior to GLib 2.10, it specified the number of pre-allocated (cached) instances to reserve memory for (0 indicates no caching). Since GLib 2.10, it is ignored, since instances are allocated with the [slice allocator][glib-Memory-Slices] now. Location of the instance initialization function (optional, for instantiatable types only) A #GTypeValueTable function table for generic handling of GValues of this type (usually only useful for fundamental types) An opaque structure used as the base of all type instances.

An opaque structure used as the base of all interface types. Returns the corresponding #GTypeInterface structure of the parent type of the instance type to which @g_iface belongs. This is useful when deriving the implementation of an interface from the parent type and then possibly overriding some methods.

the corresponding #GTypeInterface structure of the parent type of the instance type to which @g_iface belongs, or %NULL if the parent type doesn't conform to the interface

a #GTypeInterface structure

Adds @prerequisite_type to the list of prerequisites of @interface_type. This means that any type implementing @interface_type must also implement @prerequisite_type. Prerequisites can be thought of as an alternative to interface derivation (which GType doesn't support). An interface can have at most one instantiatable prerequisite type.

#GType value of an interface type #GType value of an interface or instantiatable type Returns the #GTypePlugin structure for the dynamic interface @interface_type which has been added to @instance_type, or %NULL if @interface_type has not been added to @instance_type or does not have a #GTypePlugin structure. See g_type_add_interface_dynamic().

the #GTypePlugin for the dynamic interface @interface_type of @instance_type

#GType of an instantiatable type #GType of an interface type Returns the #GTypeInterface structure of an interface to which the passed in class conforms.

the #GTypeInterface structure of @iface_type if implemented by @instance_class, %NULL otherwise

a #GTypeClass structure an interface ID which this class conforms to Returns the prerequisites of an interfaces type.

a newly-allocated zero-terminated array of #GType containing the prerequisites of @interface_type

an interface type location to return the number of prerequisites, or %NULL A callback called after an interface vtable is initialized. See g_type_add_interface_check().

data passed to g_type_add_interface_check() the interface that has been initialized #GTypeModule provides a simple implementation of the #GTypePlugin interface. The model of #GTypeModule is a dynamically loaded module which implements some number of types and interface implementations. When the module is loaded, it registers its types and interfaces using g_type_module_register_type() and g_type_module_add_interface(). As long as any instances of these types and interface implementations are in use, the module is kept loaded. When the types and interfaces are gone, the module may be unloaded. If the types and interfaces become used again, the module will be reloaded. Note that the last unref cannot happen in module code, since that would lead to the caller's code being unloaded before g_object_unref() returns to it. Keeping track of whether the module should be loaded or not is done by using a use count - it starts at zero, and whenever it is greater than zero, the module is loaded. The use count is maintained internally by the type system, but also can be explicitly controlled by g_type_module_use() and g_type_module_unuse(). Typically, when loading a module for the first type, g_type_module_use() will be used to load it so that it can initialize its types. At some later point, when the module no longer needs to be loaded except for the type implementations it contains, g_type_module_unuse() is called. #GTypeModule does not actually provide any implementation of module loading and unloading. To create a particular module type you must derive from #GTypeModule and implement the load and unload functions in #GTypeModuleClass.

Registers an additional interface for a type, whose interface lives in the given type plugin. If the interface was already registered for the type in this plugin, nothing will be done. As long as any instances of the type exist, the type plugin will not be unloaded. Since 2.56 if @module is %NULL this will call g_type_add_interface_static() instead. This can be used when making a static build of the module.

a #GTypeModule

type to which to add the interface. interface type to add type information structure Looks up or registers an enumeration that is implemented with a particular type plugin. If a type with name @type_name was previously registered, the #GType identifier for the type is returned, otherwise the type is newly registered, and the resulting #GType identifier returned. As long as any instances of the type exist, the type plugin will not be unloaded. Since 2.56 if @module is %NULL this will call g_type_register_static() instead. This can be used when making a static build of the module.

the new or existing type ID

a #GTypeModule

name for the type an array of #GEnumValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0. Looks up or registers a flags type that is implemented with a particular type plugin. If a type with name @type_name was previously registered, the #GType identifier for the type is returned, otherwise the type is newly registered, and the resulting #GType identifier returned. As long as any instances of the type exist, the type plugin will not be unloaded. Since 2.56 if @module is %NULL this will call g_type_register_static() instead. This can be used when making a static build of the module.

the new or existing type ID

a #GTypeModule

name for the type an array of #GFlagsValue structs for the possible flags values. The array is terminated by a struct with all members being 0. Looks up or registers a type that is implemented with a particular type plugin. If a type with name @type_name was previously registered, the #GType identifier for the type is returned, otherwise the type is newly registered, and the resulting #GType identifier returned. When reregistering a type (typically because a module is unloaded then reloaded, and reinitialized), @module and @parent_type must be the same as they were previously. As long as any instances of the type exist, the type plugin will not be unloaded. Since 2.56 if @module is %NULL this will call g_type_register_static() instead. This can be used when making a static build of the module.

the new or existing type ID

a #GTypeModule

the type for the parent class name for the type type information structure flags field providing details about the type Sets the name for a #GTypeModule

a #GTypeModule.

a human-readable name to use in error messages. Decreases the use count of a #GTypeModule by one. If the result is zero, the module will be unloaded. (However, the #GTypeModule will not be freed, and types associated with the #GTypeModule are not unregistered. Once a #GTypeModule is initialized, it must exist forever.)

a #GTypeModule

Increases the use count of a #GTypeModule by one. If the use count was zero before, the plugin will be loaded. If loading the plugin fails, the use count is reset to its prior value.

%FALSE if the plugin needed to be loaded and loading the plugin failed.

a #GTypeModule

the name of the module In order to implement dynamic loading of types based on #GTypeModule, the @load and @unload functions in #GTypeModuleClass must be implemented. the parent class

The GObject type system supports dynamic loading of types. The #GTypePlugin interface is used to handle the lifecycle of dynamically loaded types. It goes as follows: 1. The type is initially introduced (usually upon loading the module the first time, or by your main application that knows what modules introduces what types), like this: |[ new_type_id = g_type_register_dynamic (parent_type_id, "TypeName", new_type_plugin, type_flags); ]| where @new_type_plugin is an implementation of the #GTypePlugin interface. 2. The type's implementation is referenced, e.g. through g_type_class_ref() or through g_type_create_instance() (this is being called by g_object_new()) or through one of the above done on a type derived from @new_type_id. 3. This causes the type system to load the type's implementation by calling g_type_plugin_use() and g_type_plugin_complete_type_info() on @new_type_plugin. 4. At some point the type's implementation isn't required anymore, e.g. after g_type_class_unref() or g_type_free_instance() (called when the reference count of an instance drops to zero). 5. This causes the type system to throw away the information retrieved from g_type_plugin_complete_type_info() and then it calls g_type_plugin_unuse() on @new_type_plugin. 6. Things may repeat from the second step. So basically, you need to implement a #GTypePlugin type that carries a use_count, once use_count goes from zero to one, you need to load the implementation to successfully handle the upcoming g_type_plugin_complete_type_info() call. Later, maybe after succeeding use/unuse calls, once use_count drops to zero, you can unload the implementation again. The type system makes sure to call g_type_plugin_use() and g_type_plugin_complete_type_info() again when the type is needed again. #GTypeModule is an implementation of #GTypePlugin that already implements most of this except for the actual module loading and unloading. It even handles multiple registered types per module. Calls the @complete_interface_info function from the #GTypePluginClass of @plugin. There should be no need to use this function outside of the GObject type system itself.

the #GTypePlugin

the #GType of an instantiable type to which the interface is added the #GType of the interface whose info is completed the #GInterfaceInfo to fill in Calls the @complete_type_info function from the #GTypePluginClass of @plugin. There should be no need to use this function outside of the GObject type system itself.

a #GTypePlugin

the #GType whose info is completed the #GTypeInfo struct to fill in the #GTypeValueTable to fill in Calls the @unuse_plugin function from the #GTypePluginClass of @plugin. There should be no need to use this function outside of the GObject type system itself.

a #GTypePlugin

Calls the @use_plugin function from the #GTypePluginClass of @plugin. There should be no need to use this function outside of the GObject type system itself.

a #GTypePlugin

The #GTypePlugin interface is used by the type system in order to handle the lifecycle of dynamically loaded types. Increases the use count of the plugin. Decreases the use count of the plugin. Fills in the #GTypeInfo and #GTypeValueTable structs for the type. The structs are initialized with `memset(s, 0, sizeof (s))` before calling this function. Fills in missing parts of the #GInterfaceInfo for the interface. The structs is initialized with `memset(s, 0, sizeof (s))` before calling this function. The type of the @complete_interface_info function of #GTypePluginClass.

the #GTypePlugin the #GType of an instantiable type to which the interface is added the #GType of the interface whose info is completed the #GInterfaceInfo to fill in The type of the @complete_type_info function of #GTypePluginClass.

the #GTypePlugin the #GType whose info is completed the #GTypeInfo struct to fill in the #GTypeValueTable to fill in The type of the @unuse_plugin function of #GTypePluginClass.

the #GTypePlugin whose use count should be decreased The type of the @use_plugin function of #GTypePluginClass, which gets called to increase the use count of @plugin.

the #GTypePlugin whose use count should be increased A structure holding information for a specific type. It is filled in by the g_type_query() function. the #GType value of the type the name of the type the size of the class structure the size of the instance structure The #GTypeValueTable provides the functions required by the #GValue implementation, to serve as a container for values of a type.

A string format describing how to collect the contents of this value bit-by-bit. Each character in the format represents an argument to be collected, and the characters themselves indicate the type of the argument. Currently supported arguments are: - 'i' - Integers. passed as collect_values[].v_int. - 'l' - Longs. passed as collect_values[].v_long. - 'd' - Doubles. passed as collect_values[].v_double. - 'p' - Pointers. passed as collect_values[].v_pointer. It should be noted that for variable argument list construction, ANSI C promotes every type smaller than an integer to an int, and floats to doubles. So for collection of short int or char, 'i' needs to be used, and for collection of floats 'd'.

Format description of the arguments to collect for @lcopy_value, analogous to @collect_format. Usually, @lcopy_format string consists only of 'p's to provide lcopy_value() with pointers to storage locations.

Returns the location of the #GTypeValueTable associated with @type. Note that this function should only be used from source code that implements or has internal knowledge of the implementation of @type.

location of the #GTypeValueTable associated with @type or %NULL if there is no #GTypeValueTable associated with @type

a #GType

Checks if @value holds (or contains) a value of @type. This macro will also check for @value != %NULL and issue a warning if the check fails. A #GValue structure. A #GType value.

Checks whether the given #GValue can hold values of type %G_TYPE_BOOLEAN. a valid #GValue structure

Checks whether the given #GValue can hold values derived from type %G_TYPE_BOXED. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_CHAR. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_DOUBLE. a valid #GValue structure

Checks whether the given #GValue can hold values derived from type %G_TYPE_ENUM. a valid #GValue structure

Checks whether the given #GValue can hold values derived from type %G_TYPE_FLAGS. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_FLOAT. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_GTYPE. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_INT. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_INT64. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_LONG. a valid #GValue structure

Checks whether the given #GValue can hold values derived from type %G_TYPE_OBJECT. a valid #GValue structure

Checks whether the given #GValue can hold values derived from type %G_TYPE_PARAM. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_POINTER. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_STRING. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_UCHAR. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_UINT. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_UINT64. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_ULONG. a valid #GValue structure

Checks whether the given #GValue can hold values of type %G_TYPE_VARIANT. a valid #GValue structure

For string values, indicates that the string contained is canonical and will exist for the duration of the process. See g_value_set_interned_string().

Checks whether @value contains a string which is canonical. a valid #GValue structure

If passed to G_VALUE_COLLECT(), allocated data won't be copied but used verbatim. This does not affect ref-counted types like objects. This does not affect usage of g_value_copy(), the data will be copied if it is not ref-counted.

Get the type identifier of @value. A #GValue structure.

Gets the type name of @value. A #GValue structure.

This is the signature of va_list marshaller functions, an optional marshaller that can be used in some situations to avoid marshalling the signal argument into GValues.

the #GClosure to which the marshaller belongs a #GValue to store the return value. May be %NULL if the callback of @closure doesn't return a value. the instance on which the closure is invoked. va_list of arguments to be passed to the closure. additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() the length of the @param_types array the #GType of each argument from @args. An opaque structure used to hold different types of values. The data within the structure has protected scope: it is accessible only to functions within a #GTypeValueTable structure, or implementations of the g_value_*() API. That is, code portions which implement new fundamental types. #GValue users cannot make any assumptions about how data is stored within the 2 element @data union, and the @g_type member should only be accessed through the G_VALUE_TYPE() macro. Copies the value of @src_value into @dest_value.

An initialized #GValue structure.

An initialized #GValue structure of the same type as @src_value. Get the contents of a %G_TYPE_BOXED derived #GValue. Upon getting, the boxed value is duplicated and needs to be later freed with g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (@value), return_value);

boxed contents of @value

a valid #GValue of %G_TYPE_BOXED derived type

Get the contents of a %G_TYPE_OBJECT derived #GValue, increasing its reference count. If the contents of the #GValue are %NULL, then %NULL will be returned.

object content of @value, should be unreferenced when no longer needed.

a valid #GValue whose type is derived from %G_TYPE_OBJECT

Get the contents of a %G_TYPE_PARAM #GValue, increasing its reference count.

#GParamSpec content of @value, should be unreferenced when no longer needed.

a valid #GValue whose type is derived from %G_TYPE_PARAM

Get a copy the contents of a %G_TYPE_STRING #GValue.

a newly allocated copy of the string content of @value

a valid #GValue of type %G_TYPE_STRING

Get the contents of a variant #GValue, increasing its refcount. The returned #GVariant is never floating.

variant contents of @value (may be %NULL); should be unreffed using g_variant_unref() when no longer needed

a valid #GValue of type %G_TYPE_VARIANT

Determines if @value will fit inside the size of a pointer value. This is an internal function introduced mainly for C marshallers.

%TRUE if @value will fit inside a pointer value.

An initialized #GValue structure.

Get the contents of a %G_TYPE_BOOLEAN #GValue.

boolean contents of @value

a valid #GValue of type %G_TYPE_BOOLEAN

Get the contents of a %G_TYPE_BOXED derived #GValue.

boxed contents of @value

a valid #GValue of %G_TYPE_BOXED derived type

Do not use this function; it is broken on platforms where the %char type is unsigned, such as ARM and PowerPC. See g_value_get_schar(). Get the contents of a %G_TYPE_CHAR #GValue.

This function's return type is broken, see g_value_get_schar()

character contents of @value

a valid #GValue of type %G_TYPE_CHAR

Get the contents of a %G_TYPE_DOUBLE #GValue.

double contents of @value

a valid #GValue of type %G_TYPE_DOUBLE

Get the contents of a %G_TYPE_ENUM #GValue.

enum contents of @value

a valid #GValue whose type is derived from %G_TYPE_ENUM

Get the contents of a %G_TYPE_FLAGS #GValue.

flags contents of @value

a valid #GValue whose type is derived from %G_TYPE_FLAGS

Get the contents of a %G_TYPE_FLOAT #GValue.

float contents of @value

a valid #GValue of type %G_TYPE_FLOAT

Get the contents of a %G_TYPE_GTYPE #GValue.

the #GType stored in @value

a valid #GValue of type %G_TYPE_GTYPE

Get the contents of a %G_TYPE_INT #GValue.

integer contents of @value

a valid #GValue of type %G_TYPE_INT

Get the contents of a %G_TYPE_INT64 #GValue.

64bit integer contents of @value

a valid #GValue of type %G_TYPE_INT64

Get the contents of a %G_TYPE_LONG #GValue.

long integer contents of @value

a valid #GValue of type %G_TYPE_LONG

Get the contents of a %G_TYPE_OBJECT derived #GValue.

object contents of @value

a valid #GValue of %G_TYPE_OBJECT derived type

Get the contents of a %G_TYPE_PARAM #GValue.

#GParamSpec content of @value

a valid #GValue whose type is derived from %G_TYPE_PARAM

Get the contents of a pointer #GValue.

pointer contents of @value

a valid #GValue of %G_TYPE_POINTER

Get the contents of a %G_TYPE_CHAR #GValue.

signed 8 bit integer contents of @value

a valid #GValue of type %G_TYPE_CHAR

Get the contents of a %G_TYPE_STRING #GValue.

string content of @value

a valid #GValue of type %G_TYPE_STRING

Get the contents of a %G_TYPE_UCHAR #GValue.

unsigned character contents of @value

a valid #GValue of type %G_TYPE_UCHAR

Get the contents of a %G_TYPE_UINT #GValue.

unsigned integer contents of @value

a valid #GValue of type %G_TYPE_UINT

Get the contents of a %G_TYPE_UINT64 #GValue.

unsigned 64bit integer contents of @value

a valid #GValue of type %G_TYPE_UINT64

Get the contents of a %G_TYPE_ULONG #GValue.

unsigned long integer contents of @value

a valid #GValue of type %G_TYPE_ULONG

Get the contents of a variant #GValue.

variant contents of @value (may be %NULL)

a valid #GValue of type %G_TYPE_VARIANT

Initializes @value with the default value of @type.

the #GValue structure that has been passed in

A zero-filled (uninitialized) #GValue structure.

Type the #GValue should hold values of. Initializes and sets @value from an instantiatable type via the value_table's collect_value() function. Note: The @value will be initialised with the exact type of @instance. If you wish to set the @value's type to a different GType (such as a parent class GType), you need to manually call g_value_init() and g_value_set_instance().

An uninitialized #GValue structure.

the instance Returns the value contents as pointer. This function asserts that g_value_fits_pointer() returned %TRUE for the passed in value. This is an internal function introduced mainly for C marshallers.

the value contents as pointer

An initialized #GValue structure

Clears the current value in @value and resets it to the default value (as if the value had just been initialized).

the #GValue structure that has been passed in

An initialized #GValue structure.

Set the contents of a %G_TYPE_BOOLEAN #GValue to @v_boolean.

a valid #GValue of type %G_TYPE_BOOLEAN

boolean value to be set Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed.

a valid #GValue of %G_TYPE_BOXED derived type

boxed value to be set This is an internal function introduced mainly for C marshallers.

Use g_value_take_boxed() instead.

a valid #GValue of %G_TYPE_BOXED derived type

duplicated unowned boxed value to be set Set the contents of a %G_TYPE_CHAR #GValue to @v_char.

This function's input type is broken, see g_value_set_schar()

a valid #GValue of type %G_TYPE_CHAR

character value to be set Set the contents of a %G_TYPE_DOUBLE #GValue to @v_double.

a valid #GValue of type %G_TYPE_DOUBLE

double value to be set Set the contents of a %G_TYPE_ENUM #GValue to @v_enum.

a valid #GValue whose type is derived from %G_TYPE_ENUM

enum value to be set Set the contents of a %G_TYPE_FLAGS #GValue to @v_flags.

a valid #GValue whose type is derived from %G_TYPE_FLAGS

flags value to be set Set the contents of a %G_TYPE_FLOAT #GValue to @v_float.

a valid #GValue of type %G_TYPE_FLOAT

float value to be set Set the contents of a %G_TYPE_GTYPE #GValue to @v_gtype.

a valid #GValue of type %G_TYPE_GTYPE

#GType to be set Sets @value from an instantiatable type via the value_table's collect_value() function.

An initialized #GValue structure.

the instance Set the contents of a %G_TYPE_INT #GValue to @v_int.

a valid #GValue of type %G_TYPE_INT

integer value to be set Set the contents of a %G_TYPE_INT64 #GValue to @v_int64.

a valid #GValue of type %G_TYPE_INT64

64bit integer value to be set Set the contents of a %G_TYPE_STRING #GValue to @v_string. The string is assumed to be static and interned (canonical, for example from g_intern_string()), and is thus not duplicated when setting the #GValue.

a valid #GValue of type %G_TYPE_STRING

static string to be set Set the contents of a %G_TYPE_LONG #GValue to @v_long.

a valid #GValue of type %G_TYPE_LONG

long integer value to be set Set the contents of a %G_TYPE_OBJECT derived #GValue to @v_object. g_value_set_object() increases the reference count of @v_object (the #GValue holds a reference to @v_object). If you do not wish to increase the reference count of the object (i.e. you wish to pass your current reference to the #GValue because you no longer need it), use g_value_take_object() instead. It is important that your #GValue holds a reference to @v_object (either its own, or one it has taken) to ensure that the object won't be destroyed while the #GValue still exists).

a valid #GValue of %G_TYPE_OBJECT derived type

object value to be set This is an internal function introduced mainly for C marshallers.

Use g_value_take_object() instead.

a valid #GValue of %G_TYPE_OBJECT derived type

object value to be set Set the contents of a %G_TYPE_PARAM #GValue to @param.

a valid #GValue of type %G_TYPE_PARAM

the #GParamSpec to be set This is an internal function introduced mainly for C marshallers.

Use g_value_take_param() instead.

a valid #GValue of type %G_TYPE_PARAM

the #GParamSpec to be set Set the contents of a pointer #GValue to @v_pointer.

a valid #GValue of %G_TYPE_POINTER

pointer value to be set Set the contents of a %G_TYPE_CHAR #GValue to @v_char.

a valid #GValue of type %G_TYPE_CHAR

signed 8 bit integer to be set Set the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed. The boxed value is assumed to be static, and is thus not duplicated when setting the #GValue.

a valid #GValue of %G_TYPE_BOXED derived type

static boxed value to be set Set the contents of a %G_TYPE_STRING #GValue to @v_string. The string is assumed to be static, and is thus not duplicated when setting the #GValue. If the the string is a canonical string, using g_value_set_interned_string() is more appropriate.

a valid #GValue of type %G_TYPE_STRING

static string to be set Set the contents of a %G_TYPE_STRING #GValue to @v_string.

a valid #GValue of type %G_TYPE_STRING

caller-owned string to be duplicated for the #GValue This is an internal function introduced mainly for C marshallers.

Use g_value_take_string() instead.

a valid #GValue of type %G_TYPE_STRING

duplicated unowned string to be set Set the contents of a %G_TYPE_UCHAR #GValue to @v_uchar.

a valid #GValue of type %G_TYPE_UCHAR

unsigned character value to be set Set the contents of a %G_TYPE_UINT #GValue to @v_uint.

a valid #GValue of type %G_TYPE_UINT

unsigned integer value to be set Set the contents of a %G_TYPE_UINT64 #GValue to @v_uint64.

a valid #GValue of type %G_TYPE_UINT64

unsigned 64bit integer value to be set Set the contents of a %G_TYPE_ULONG #GValue to @v_ulong.

a valid #GValue of type %G_TYPE_ULONG

unsigned long integer value to be set Set the contents of a variant #GValue to @variant. If the variant is floating, it is consumed.

a valid #GValue of type %G_TYPE_VARIANT

a #GVariant, or %NULL Sets the contents of a %G_TYPE_BOXED derived #GValue to @v_boxed and takes over the ownership of the caller’s reference to @v_boxed; the caller doesn’t have to unref it any more.

a valid #GValue of %G_TYPE_BOXED derived type

duplicated unowned boxed value to be set Sets the contents of a %G_TYPE_OBJECT derived #GValue to @v_object and takes over the ownership of the caller’s reference to @v_object; the caller doesn’t have to unref it any more (i.e. the reference count of the object is not increased). If you want the #GValue to hold its own reference to @v_object, use g_value_set_object() instead.

a valid #GValue of %G_TYPE_OBJECT derived type

object value to be set Sets the contents of a %G_TYPE_PARAM #GValue to @param and takes over the ownership of the caller’s reference to @param; the caller doesn’t have to unref it any more.

a valid #GValue of type %G_TYPE_PARAM

the #GParamSpec to be set Sets the contents of a %G_TYPE_STRING #GValue to @v_string.

a valid #GValue of type %G_TYPE_STRING

string to take ownership of Set the contents of a variant #GValue to @variant, and takes over the ownership of the caller's reference to @variant; the caller doesn't have to unref it any more (i.e. the reference count of the variant is not increased). If @variant was floating then its floating reference is converted to a hard reference. If you want the #GValue to hold its own reference to @variant, use g_value_set_variant() instead. This is an internal function introduced mainly for C marshallers.

a valid #GValue of type %G_TYPE_VARIANT

a #GVariant, or %NULL Tries to cast the contents of @src_value into a type appropriate to store in @dest_value, e.g. to transform a %G_TYPE_INT value into a %G_TYPE_FLOAT value. Performing transformations between value types might incur precision lossage. Especially transformations into strings might reveal seemingly arbitrary results and shouldn't be relied upon for production code (such as rcfile value or object property serialization).

Whether a transformation rule was found and could be applied. Upon failing transformations, @dest_value is left untouched.

Source value.

Target value. Clears the current value in @value (if any) and "unsets" the type, this releases all resources associated with this GValue. An unset value is the same as an uninitialized (zero-filled) #GValue structure.

An initialized #GValue structure.

Registers a value transformation function for use in g_value_transform(). A previously registered transformation function for @src_type and @dest_type will be replaced.

Source type. Target type. a function which transforms values of type @src_type into value of type @dest_type Returns whether a #GValue of type @src_type can be copied into a #GValue of type @dest_type.

%TRUE if g_value_copy() is possible with @src_type and @dest_type.

source type to be copied. destination type for copying. Check whether g_value_transform() is able to transform values of type @src_type into values of type @dest_type. Note that for the types to be transformable, they must be compatible or a transformation function must be registered.

%TRUE if the transformation is possible, %FALSE otherwise.

Source type. Target type. A #GValueArray contains an array of #GValue elements. number of values contained in the array array of values Allocate and initialize a new #GValueArray, optionally preserve space for @n_prealloced elements. New arrays always contain 0 elements, regardless of the value of @n_prealloced.

Use #GArray and g_array_sized_new() instead.

a newly allocated #GValueArray with 0 values

number of values to preallocate space for Insert a copy of @value as last element of @value_array. If @value is %NULL, an uninitialized value is appended.

Use #GArray and g_array_append_val() instead.

the #GValueArray passed in as @value_array

#GValueArray to add an element to

#GValue to copy into #GValueArray, or %NULL Construct an exact copy of a #GValueArray by duplicating all its contents.

Use #GArray and g_array_ref() instead.

Newly allocated copy of #GValueArray

#GValueArray to copy

Free a #GValueArray including its contents.

Use #GArray and g_array_unref() instead.

#GValueArray to free

Return a pointer to the value at @index_ containd in @value_array.

Use g_array_index() instead.

pointer to a value at @index_ in @value_array

#GValueArray to get a value from

index of the value of interest Insert a copy of @value at specified position into @value_array. If @value is %NULL, an uninitialized value is inserted.

Use #GArray and g_array_insert_val() instead.

the #GValueArray passed in as @value_array

#GValueArray to add an element to

insertion position, must be <= value_array->;n_values #GValue to copy into #GValueArray, or %NULL Insert a copy of @value as first element of @value_array. If @value is %NULL, an uninitialized value is prepended.

Use #GArray and g_array_prepend_val() instead.

the #GValueArray passed in as @value_array

#GValueArray to add an element to

#GValue to copy into #GValueArray, or %NULL Remove the value at position @index_ from @value_array.

Use #GArray and g_array_remove_index() instead.

the #GValueArray passed in as @value_array

#GValueArray to remove an element from

position of value to remove, which must be less than @value_array->n_values Sort @value_array using @compare_func to compare the elements according to the semantics of #GCompareFunc. The current implementation uses the same sorting algorithm as standard C qsort() function.

Use #GArray and g_array_sort().

the #GValueArray passed in as @value_array

#GValueArray to sort

function to compare elements Sort @value_array using @compare_func to compare the elements according to the semantics of #GCompareDataFunc. The current implementation uses the same sorting algorithm as standard C qsort() function.

Use #GArray and g_array_sort_with_data().

the #GValueArray passed in as @value_array

#GValueArray to sort

function to compare elements extra data argument provided for @compare_func The type of value transformation functions which can be registered with g_value_register_transform_func(). @dest_value will be initialized to the correct destination type.

Source value. Target value. A #GWeakNotify function can be added to an object as a callback that gets triggered when the object is finalized. Since the object is already being finalized when the #GWeakNotify is called, there's not much you could do with the object, apart from e.g. using its address as hash-index or the like.

data that was provided when the weak reference was established the object being finalized A structure containing a weak reference to a #GObject. It can either be empty (i.e. point to %NULL), or point to an object for as long as at least one "strong" reference to that object exists. Before the object's #GObjectClass.dispose method is called, every #GWeakRef associated with becomes empty (i.e. points to %NULL). Like #GValue, #GWeakRef can be statically allocated, stack- or heap-allocated, or embedded in larger structures. Unlike g_object_weak_ref() and g_object_add_weak_pointer(), this weak reference is thread-safe: converting a weak pointer to a reference is atomic with respect to invalidation of weak pointers to destroyed objects. If the object's #GObjectClass.dispose method results in additional references to the object being held, any #GWeakRefs taken before it was disposed will continue to point to %NULL. If #GWeakRefs are taken after the object is disposed and re-referenced, they will continue to point to it until its refcount goes back to zero, at which point they too will be invalidated. Frees resources associated with a non-statically-allocated #GWeakRef. After this call, the #GWeakRef is left in an undefined state. You should only call this on a #GWeakRef that previously had g_weak_ref_init() called on it.

location of a weak reference, which may be empty

If @weak_ref is not empty, atomically acquire a strong reference to the object it points to, and return that reference. This function is needed because of the potential race between taking the pointer value and g_object_ref() on it, if the object was losing its last reference at the same time in a different thread. The caller should release the resulting reference in the usual way, by using g_object_unref().

the object pointed to by @weak_ref, or %NULL if it was empty

location of a weak reference to a #GObject

Initialise a non-statically-allocated #GWeakRef. This function also calls g_weak_ref_set() with @object on the freshly-initialised weak reference. This function should always be matched with a call to g_weak_ref_clear(). It is not necessary to use this function for a #GWeakRef in static storage because it will already be properly initialised. Just use g_weak_ref_set() directly.

uninitialized or empty location for a weak reference

a #GObject or %NULL Change the object to which @weak_ref points, or set it to %NULL. You must own a strong reference on @object while calling this function.

location for a weak reference

a #GObject or %NULL

Assert that @object is non-%NULL, then release one reference to it with g_object_unref() and assert that it has been finalized (i.e. that there are no more references). If assertions are disabled via `G_DISABLE_ASSERT`, this macro just calls g_object_unref() without any further checks. This macro should only be used in regression tests. an object

Provide a copy of a boxed structure @src_boxed which is of type @boxed_type.

The newly created copy of the boxed structure.

The type of @src_boxed. The boxed structure to be copied. Free the boxed structure @boxed which is of type @boxed_type.

The type of @boxed. The boxed structure to be freed. This function creates a new %G_TYPE_BOXED derived type id for a new boxed type with name @name. Boxed type handling functions have to be provided to copy and free opaque boxed structures of this type.

New %G_TYPE_BOXED derived type id for @name.

Name of the new boxed type. Boxed structure copy function. Boxed structure free function. A #GClosureMarshal function for use with signals with handlers that take two boxed pointers as arguments and return a boolean. If you have such a signal, you will probably also need to use an accumulator, such as g_signal_accumulator_true_handled().

A #GClosure. A #GValue to store the return value. May be %NULL if the callback of closure doesn't return a value. The length of the @param_values array. An array of #GValues holding the arguments on which to invoke the callback of closure. The invocation hint given as the last argument to g_closure_invoke(). Additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() A marshaller for a #GCClosure with a callback of type `gboolean (*callback) (gpointer instance, gint arg1, gpointer user_data)` where the #gint parameter denotes a flags type.

the #GClosure to which the marshaller belongs a #GValue which can store the returned #gboolean 2 a #GValue array holding instance and arg1 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `gchar* (*callback) (gpointer instance, GObject *arg1, gpointer arg2, gpointer user_data)`.

the #GClosure to which the marshaller belongs a #GValue, which can store the returned string 3 a #GValue array holding instance, arg1 and arg2 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gboolean arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gboolean parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, GBoxed *arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GBoxed* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gchar arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gchar parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gdouble arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gdouble parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gint arg1, gpointer user_data)` where the #gint parameter denotes an enumeration type..

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the enumeration parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gint arg1, gpointer user_data)` where the #gint parameter denotes a flags type.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the flags parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gfloat arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gfloat parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gint arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gint parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, glong arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #glong parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, GObject *arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GObject* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, GParamSpec *arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GParamSpec* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gpointer arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gpointer parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, const gchar *arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gchar* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, guchar arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #guchar parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, guint arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 3 a #GValue array holding instance, arg1 and arg2 the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gulong arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #gulong parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, GVariant *arg1, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 2 a #GValue array holding the instance and the #GVariant* parameter the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A marshaller for a #GCClosure with a callback of type `void (*callback) (gpointer instance, gpointer user_data)`.

the #GClosure to which the marshaller belongs ignored 1 a #GValue array holding only the instance the invocation hint given as the last argument to g_closure_invoke() additional data specified when registering the marshaller A generic marshaller function implemented via [libffi](http://sourceware.org/libffi/). Normally this function is not passed explicitly to g_signal_new(), but used automatically by GLib when specifying a %NULL marshaller.

A #GClosure. A #GValue to store the return value. May be %NULL if the callback of closure doesn't return a value. The length of the @param_values array. An array of #GValues holding the arguments on which to invoke the callback of closure. The invocation hint given as the last argument to g_closure_invoke(). Additional data specified when registering the marshaller, see g_closure_set_marshal() and g_closure_set_meta_marshal() Creates a new closure which invokes @callback_func with @user_data as the last parameter. @destroy_data will be called as a finalize notifier on the #GClosure.

a floating reference to a new #GCClosure

a new #GCClosure

a floating reference to a new #GCClosure

the function to invoke user data to pass to @callback_func destroy notify to be called when @user_data is no longer used Clears a reference to a #GObject. @object_ptr must not be %NULL. If the reference is %NULL then this function does nothing. Otherwise, the reference count of the object is decreased and the pointer is set to %NULL. A macro is also included that allows this function to be used without pointer casts.

a pointer to a #GObject reference Disconnects a handler from @instance so it will not be called during any future or currently ongoing emissions of the signal it has been connected to. The @handler_id_ptr is then set to zero, which is never a valid handler ID value (see g_signal_connect()). If the handler ID is 0 then this function does nothing. A macro is also included that allows this function to be used without pointer casts.

A pointer to a handler ID (of type #gulong) of the handler to be disconnected. The instance to remove the signal handler from.

Clears a weak reference to a #GObject. @weak_pointer_location must not be %NULL. If the weak reference is %NULL then this function does nothing. Otherwise, the weak reference to the object is removed for that location and the pointer is set to %NULL. A macro is also included that allows this function to be used without pointer casts. The function itself is static inline, so its address may vary between compilation units. The memory address of a pointer

This function is meant to be called from the `complete_type_info` function of a #GTypePlugin implementation, as in the following example: |[ static void my_enum_complete_type_info (GTypePlugin *plugin, GType g_type, GTypeInfo *info, GTypeValueTable *value_table) { static const GEnumValue values[] = { { MY_ENUM_FOO, "MY_ENUM_FOO", "foo" }, { MY_ENUM_BAR, "MY_ENUM_BAR", "bar" }, { 0, NULL, NULL } }; g_enum_complete_type_info (type, info, values); } ]|

the type identifier of the type being completed the #GTypeInfo struct to be filled in An array of #GEnumValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0. Returns the #GEnumValue for a value.

the #GEnumValue for @value, or %NULL if @value is not a member of the enumeration

a #GEnumClass the value to look up Looks up a #GEnumValue by name.

the #GEnumValue with name @name, or %NULL if the enumeration doesn't have a member with that name

a #GEnumClass the name to look up Looks up a #GEnumValue by nickname.

the #GEnumValue with nickname @nick, or %NULL if the enumeration doesn't have a member with that nickname

a #GEnumClass the nickname to look up Registers a new static enumeration type with the name @name. It is normally more convenient to let [glib-mkenums][glib-mkenums], generate a my_enum_get_type() function from a usual C enumeration definition than to write one yourself using g_enum_register_static().

The new type identifier.

A nul-terminated string used as the name of the new type. An array of #GEnumValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0. GObject keeps a reference to the data, so it cannot be stack-allocated. Pretty-prints @value in the form of the enum’s name. This is intended to be used for debugging purposes. The format of the output may change in the future.

a newly-allocated text string

the type identifier of a #GEnumClass type the value The GLib type system provides fundamental types for enumeration and flags types. (Flags types are like enumerations, but allow their values to be combined by bitwise or). A registered enumeration or flags type associates a name and a nickname with each allowed value, and the methods g_enum_get_value_by_name(), g_enum_get_value_by_nick(), g_flags_get_value_by_name() and g_flags_get_value_by_nick() can look up values by their name or nickname. When an enumeration or flags type is registered with the GLib type system, it can be used as value type for object properties, using g_param_spec_enum() or g_param_spec_flags(). GObject ships with a utility called [glib-mkenums][glib-mkenums], that can construct suitable type registration functions from C enumeration definitions. Example of how to get a string representation of an enum value: |[ GEnumClass *enum_class; GEnumValue *enum_value; enum_class = g_type_class_ref (MAMAN_TYPE_MY_ENUM); enum_value = g_enum_get_value (enum_class, MAMAN_MY_ENUM_FOO); g_print ("Name: %s\n", enum_value->value_name); g_type_class_unref (enum_class); ]| This function is meant to be called from the complete_type_info() function of a #GTypePlugin implementation, see the example for g_enum_complete_type_info() above.

the type identifier of the type being completed the #GTypeInfo struct to be filled in An array of #GFlagsValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0. Returns the first #GFlagsValue which is set in @value.

the first #GFlagsValue which is set in @value, or %NULL if none is set

a #GFlagsClass the value Looks up a #GFlagsValue by name.

the #GFlagsValue with name @name, or %NULL if there is no flag with that name

a #GFlagsClass the name to look up Looks up a #GFlagsValue by nickname.

the #GFlagsValue with nickname @nick, or %NULL if there is no flag with that nickname

a #GFlagsClass the nickname to look up Registers a new static flags type with the name @name. It is normally more convenient to let [glib-mkenums][glib-mkenums] generate a my_flags_get_type() function from a usual C enumeration definition than to write one yourself using g_flags_register_static().

The new type identifier.

A nul-terminated string used as the name of the new type. An array of #GFlagsValue structs for the possible flags values. The array is terminated by a struct with all members being 0. GObject keeps a reference to the data, so it cannot be stack-allocated. Pretty-prints @value in the form of the flag names separated by ` | ` and sorted. Any extra bits will be shown at the end as a hexadecimal number. This is intended to be used for debugging purposes. The format of the output may change in the future.

a newly-allocated text string

the type identifier of a #GFlagsClass type the value #GBoxed is a generic wrapper mechanism for arbitrary C structures. The only thing the type system needs to know about the structures is how to copy them (a #GBoxedCopyFunc) and how to free them (a #GBoxedFreeFunc) — beyond that they are treated as opaque chunks of memory. Boxed types are useful for simple value-holder structures like rectangles or points. They can also be used for wrapping structures defined in non-#GObject based libraries. They allow arbitrary structures to be handled in a uniform way, allowing uniform copying (or referencing) and freeing (or unreferencing) of them, and uniform representation of the type of the contained structure. In turn, this allows any type which can be boxed to be set as the data in a #GValue, which allows for polymorphic handling of a much wider range of data types, and hence usage of such types as #GObject property values. #GBoxed is designed so that reference counted types can be boxed. Use the type’s ‘ref’ function as the #GBoxedCopyFunc, and its ‘unref’ function as the #GBoxedFreeFunc. For example, for #GBytes, the #GBoxedCopyFunc is g_bytes_ref(), and the #GBoxedFreeFunc is g_bytes_unref(). The #GValue structure is basically a variable container that consists of a type identifier and a specific value of that type. The type identifier within a #GValue structure always determines the type of the associated value. To create an undefined #GValue structure, simply create a zero-filled #GValue structure. To initialize the #GValue, use the g_value_init() function. A #GValue cannot be used until it is initialized. The basic type operations (such as freeing and copying) are determined by the #GTypeValueTable associated with the type ID stored in the #GValue. Other #GValue operations (such as converting values between types) are provided by this interface. The code in the example program below demonstrates #GValue's features. |[ #include <glib-object.h> static void int2string (const GValue *src_value, GValue *dest_value) { if (g_value_get_int (src_value) == 42) g_value_set_static_string (dest_value, "An important number"); else g_value_set_static_string (dest_value, "What's that?"); } int main (int argc, char *argv[]) { // GValues must be initialized GValue a = G_VALUE_INIT; GValue b = G_VALUE_INIT; const gchar *message; // The GValue starts empty g_assert (!G_VALUE_HOLDS_STRING (&a)); // Put a string in it g_value_init (&a, G_TYPE_STRING); g_assert (G_VALUE_HOLDS_STRING (&a)); g_value_set_static_string (&a, "Hello, world!"); g_printf ("%s\n", g_value_get_string (&a)); // Reset it to its pristine state g_value_unset (&a); // It can then be reused for another type g_value_init (&a, G_TYPE_INT); g_value_set_int (&a, 42); // Attempt to transform it into a GValue of type STRING g_value_init (&b, G_TYPE_STRING); // An INT is transformable to a STRING g_assert (g_value_type_transformable (G_TYPE_INT, G_TYPE_STRING)); g_value_transform (&a, &b); g_printf ("%s\n", g_value_get_string (&b)); // Attempt to transform it again using a custom transform function g_value_register_transform_func (G_TYPE_INT, G_TYPE_STRING, int2string); g_value_transform (&a, &b); g_printf ("%s\n", g_value_get_string (&b)); return 0; } ]| The GType API is the foundation of the GObject system. It provides the facilities for registering and managing all fundamental data types, user-defined object and interface types. For type creation and registration purposes, all types fall into one of two categories: static or dynamic. Static types are never loaded or unloaded at run-time as dynamic types may be. Static types are created with g_type_register_static() that gets type specific information passed in via a #GTypeInfo structure. Dynamic types are created with g_type_register_dynamic() which takes a #GTypePlugin structure instead. The remaining type information (the #GTypeInfo structure) is retrieved during runtime through #GTypePlugin and the g_type_plugin_*() API. These registration functions are usually called only once from a function whose only purpose is to return the type identifier for a specific class. Once the type (or class or interface) is registered, it may be instantiated, inherited, or implemented depending on exactly what sort of type it is. There is also a third registration function for registering fundamental types called g_type_register_fundamental() which requires both a #GTypeInfo structure and a #GTypeFundamentalInfo structure but it is seldom used since most fundamental types are predefined rather than user-defined. Type instance and class structs are limited to a total of 64 KiB, including all parent types. Similarly, type instances' private data (as created by G_ADD_PRIVATE()) are limited to a total of 64 KiB. If a type instance needs a large static buffer, allocate it separately (typically by using #GArray or #GPtrArray) and put a pointer to the buffer in the structure. As mentioned in the [GType conventions][gtype-conventions], type names must be at least three characters long. There is no upper length limit. The first character must be a letter (a–z or A–Z) or an underscore (‘_’). Subsequent characters can be letters, numbers or any of ‘-_+’.

GObject is the fundamental type providing the common attributes and methods for all object types in GTK+, Pango and other libraries based on GObject. The GObject class provides methods for object construction and destruction, property access methods, and signal support. Signals are described in detail [here][gobject-Signals]. For a tutorial on implementing a new GObject class, see [How to define and implement a new GObject][howto-gobject]. For a list of naming conventions for GObjects and their methods, see the [GType conventions][gtype-conventions]. For the high-level concepts behind GObject, read [Instantiable classed types: Objects][gtype-instantiable-classed]. ## Floating references # {#floating-ref} **Note**: Floating references are a C convenience API and should not be used in modern GObject code. Language bindings in particular find the concept highly problematic, as floating references are not identifiable through annotations, and neither are deviations from the floating reference behavior, like types that inherit from #GInitiallyUnowned and still return a full reference from g_object_new(). GInitiallyUnowned is derived from GObject. The only difference between the two is that the initial reference of a GInitiallyUnowned is flagged as a "floating" reference. This means that it is not specifically claimed to be "owned" by any code portion. The main motivation for providing floating references is C convenience. In particular, it allows code to be written as: |[ container = create_container (); container_add_child (container, create_child()); ]| If container_add_child() calls g_object_ref_sink() on the passed-in child, no reference of the newly created child is leaked. Without floating references, container_add_child() can only g_object_ref() the new child, so to implement this code without reference leaks, it would have to be written as: |[ Child *child; container = create_container (); child = create_child (); container_add_child (container, child); g_object_unref (child); ]| The floating reference can be converted into an ordinary reference by calling g_object_ref_sink(). For already sunken objects (objects that don't have a floating reference anymore), g_object_ref_sink() is equivalent to g_object_ref() and returns a new reference. Since floating references are useful almost exclusively for C convenience, language bindings that provide automated reference and memory ownership maintenance (such as smart pointers or garbage collection) should not expose floating references in their API. The best practice for handling types that have initially floating references is to immediately sink those references after g_object_new() returns, by checking if the #GType inherits from #GInitiallyUnowned. For instance: |[ GObject *res = g_object_new_with_properties (gtype, n_props, prop_names, prop_values); // or: if (g_type_is_a (gtype, G_TYPE_INITIALLY_UNOWNED)) if (G_IS_INITIALLY_UNOWNED (res)) g_object_ref_sink (res); return res; ]| Some object implementations may need to save an objects floating state across certain code portions (an example is #GtkMenu), to achieve this, the following sequence can be used: |[ // save floating state gboolean was_floating = g_object_is_floating (object); g_object_ref_sink (object); // protected code portion ... // restore floating state if (was_floating) g_object_force_floating (object); else g_object_unref (object); // release previously acquired reference ]| Creates a new #GParamSpecBoolean instance specifying a %G_TYPE_BOOLEAN property. In many cases, it may be more appropriate to use an enum with g_param_spec_enum(), both to improve code clarity by using explicitly named values, and to allow for more values to be added in future without breaking API. See g_param_spec_internal() for details on property names.