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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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;
}
]|
Since GLib 2.72, the returned `MyObjectPrivate` pointer is guaranteed to be
aligned to at least the alignment of the largest basic GLib type (typically
this is #guint64 or #gdouble). If you need larger alignment for an element in
the struct, you should allocate it on the heap (aligned), or arrange for your
`MyObjectPrivate` struct to be appropriately padded.
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.
This function 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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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 #GObject instance used as the source of the binding.
A #GBinding can outlive the source #GObject as the binding does not hold a
strong reference to the source. If the source is destroyed before the
binding then this function will return %NULL.
the source #GObject, or %NULL if the
source does not exist any more.
a #GBinding
Retrieves the #GObject instance used as the target of the binding.
A #GBinding can outlive the target #GObject as the binding does not hold a
strong reference to the target. If the target is destroyed before the
binding then this function will return %NULL.
the target #GObject, or %NULL if the
target does not exist any more.
a #GBinding
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.
A #GBinding can outlive the source #GObject as the binding does not hold a
strong reference to the source. If the source is destroyed before the
binding then this function will return %NULL.
Use g_binding_dup_source() if the source or binding are used from different
threads as otherwise the pointer returned from this function might become
invalid if the source is finalized from another thread in the meantime.
Use g_binding_dup_source() for a safer version of this
function.
the source #GObject, or %NULL if the
source does not exist any more.
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.
A #GBinding can outlive the target #GObject as the binding does not hold a
strong reference to the target. If the target is destroyed before the
binding then this function will return %NULL.
Use g_binding_dup_target() if the target or binding are used from different
threads as otherwise the pointer returned from this function might become
invalid if the target is finalized from another thread in the meantime.
Use g_binding_dup_target() for a safer version of this
function.
the target #GObject, or %NULL if the
target does not exist any more.
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 the binding is still bound; if you want to hold on
to the #GBinding instance after calling g_binding_unbind(), you will need
to hold a reference to it.
Note however that this function does not take ownership of @binding, it
only unrefs the reference that was initially created by
g_object_bind_property() and is owned by the binding.
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().
The #GBindingGroup can be used to bind multiple properties
from an object collectively.
Use the various methods to bind properties from a single source
object to multiple destination objects. Properties can be bound
bidirectionally and are connected when the source object is set
with g_binding_group_set_source().
Creates a new #GBindingGroup.
a new #GBindingGroup
Creates a binding between @source_property on the source object
and @target_property on @target. Whenever the @source_property
is changed the @target_property is updated using the same value.
The binding flag %G_BINDING_SYNC_CREATE is automatically specified.
See g_object_bind_property() for more information.
the #GBindingGroup
the property on the source to bind
the target #GObject
the property on @target to bind
the flags used to create the #GBinding
Creates a binding between @source_property on the source object and
@target_property on @target, allowing you to set the transformation
functions to be used by the binding. The binding flag
%G_BINDING_SYNC_CREATE is automatically specified.
See g_object_bind_property_full() for more information.
the #GBindingGroup
the property on the source to bind
the target #GObject
the property on @target to bind
the flags used to create the #GBinding
the transformation function
from the source object to the @target, or %NULL to use the default
the transformation function
from the @target to the source object, or %NULL to use the default
custom data to be passed to the transformation
functions, or %NULL
function to be called when disposing the binding,
to free the resources used by the transformation functions
Creates a binding between @source_property on the source object and
@target_property on @target, allowing you to set the transformation
functions to be used by the binding. The binding flag
%G_BINDING_SYNC_CREATE is automatically specified.
This function is the language bindings friendly version of
g_binding_group_bind_property_full(), using #GClosures
instead of function pointers.
See g_object_bind_property_with_closures() for more information.
the #GBindingGroup
the property on the source to bind
the target #GObject
the property on @target to bind
the flags used to create the #GBinding
a #GClosure wrapping the
transformation function from the source object to the @target,
or %NULL to use the default
a #GClosure wrapping the
transformation function from the @target to the source object,
or %NULL to use the default
Gets the source object used for binding properties.
a #GObject or %NULL.
the #GBindingGroup
Sets @source as the source object used for creating property
bindings. If there is already a source object all bindings from it
will be removed.
Note that all properties that have been bound must exist on @source.
the #GBindingGroup
the source #GObject,
or %NULL to clear it
The source object used for binding properties.
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 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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_BOOLEAN__FLAGS().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_STRING__OBJECT_POINTER().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__BOOLEAN().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__BOXED().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__CHAR().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__DOUBLE().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__ENUM().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__FLAGS().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__FLOAT().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__INT().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__LONG().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__OBJECT().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__PARAM().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__POINTER().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__STRING().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__UCHAR().
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.
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
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
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.
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__UINT().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__ULONG().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__VARIANT().
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.
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
The #GVaClosureMarshal equivalent to g_cclosure_marshal_VOID__VOID().
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.
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()
A generic #GVaClosureMarshal function implemented via
[libffi](http://sourceware.org/libffi/).
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_list.
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
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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.
For GObject's C predefined marshallers (the `g_cclosure_marshal_*()`
functions), what it provides is a callback function to use instead of
@closure->callback.
See also: g_closure_set_meta_marshal()
a #GClosure
a #GClosureMarshal function
Sets the meta marshaller of @closure.
A meta marshaller wraps the @closure's 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 the @closure's 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.
This function 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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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.
Default behaviour (no special flags). Since: 2.74
If set, the handler should be called after the
default handler of the signal. Normally, the handler is called before
the default handler.
If set, 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:
|[<!-- language="C" -->
#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
]|
Since the instance structure is public it is often needed to declare a
private struct as follow in your C file:
|[<!-- language="C" -->
typedef struct _GtkFrobberPrivate GtkFrobberPrivate;
struct _GtkFrobberPrivate
{
...
};
G_DEFINE_TYPE_WITH_PRIVATE (GtkFrobber, gtk_frobber, GTK_TYPE_WIDGET)
]|
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:
|[<!-- language="C" -->
#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
]|
And use it as follow in your C file:
|[<!-- language="C" -->
struct _MyAppWindow
{
GtkWindow parent;
...
};
G_DEFINE_TYPE (MyAppWindow, my_app_window, GTK_TYPE_WINDOW)
]|
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` type 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:
|[<!-- language="C" -->
#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
]|
And use it as follow in your C file:
|[<!-- language="C" -->
G_DEFINE_INTERFACE (MyModel, my_model, G_TYPE_OBJECT);
static void
my_model_default_init (MyModelInterface *iface)
{
...
}
]|
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 defining a new custom boxed type.
Using this macro is the recommended way of defining new custom boxed
types, over calling g_boxed_type_register_static() directly. It defines
a `type_name_get_type()` function which will return the newly defined
#GType, enabling lazy instantiation.
You might start by putting declarations in a header as follows:
|[<!-- language="C" -->
#define MY_TYPE_STRUCT my_struct_get_type ()
GType my_struct_get_type (void) G_GNUC_CONST;
MyStruct * my_struct_new (void);
void my_struct_free (MyStruct *self);
MyStruct * my_struct_copy (MyStruct *self);
]|
And then use this macro and define your implementation in the source file as
follows:
|[<!-- language="C" -->
MyStruct *
my_struct_new (void)
{
// ... your code to allocate a new MyStruct ...
}
void
my_struct_free (MyStruct *self)
{
// ... your code to free a MyStruct ...
}
MyStruct *
my_struct_copy (MyStruct *self)
{
// ... your code return a newly allocated copy of a MyStruct ...
}
G_DEFINE_BOXED_TYPE (MyStruct, my_struct, my_struct_copy, my_struct_free)
void
foo ()
{
MyStruct *ms;
ms = my_struct_new ();
// ... your code ...
my_struct_free (ms);
}
]|
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:
|[<!-- language="C" -->
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.
|[<!-- language="C" -->
G_DEFINE_DYNAMIC_TYPE_EXTENDED (GtkGadget,
gtk_gadget,
GTK_TYPE_THING,
0,
G_IMPLEMENT_INTERFACE_DYNAMIC (TYPE_GIZMO,
gtk_gadget_gizmo_init));
]|
expands to
|[<!-- language="C" -->
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 defining enumeration types.
This macro will generate a `*_get_type()` function for the
given @TypeName, using @type_name as the function prefix.
|[<!-- language="C" -->
G_DEFINE_ENUM_TYPE (GtkOrientation, gtk_orientation,
G_DEFINE_ENUM_VALUE (GTK_ORIENTATION_HORIZONTAL, "horizontal"),
G_DEFINE_ENUM_VALUE (GTK_ORIENTATION_VERTICAL, "vertical"))
]|
For projects that have multiple enumeration types, or enumeration
types with many values, you should consider using glib-mkenums to
generate the type function.
the enumeration type, in `CamelCase`
the enumeration type prefixed, in `snake_case`
a list of enumeration values, defined using G_DEFINE_ENUM_VALUE()
Defines an enumeration value, and maps it to a "nickname".
This macro can only be used with G_DEFINE_ENUM_TYPE() and
G_DEFINE_FLAGS_TYPE().
an enumeration value
a short string representing the enumeration value
A convenience macro for type implementations.
Similar to G_DEFINE_TYPE(), but defines a final 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 lower case, with words
separated by `_` (snake case)
the #GType of the parent type
A convenience macro for type implementations.
Similar to G_DEFINE_TYPE_WITH_CODE(), but defines a final 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 lower case, with words
separated by `_` (snake case)
the #GType of the parent type
Custom code that gets inserted in the `type_name_get_type()` function.
A convenience macro for type implementations.
Similar to G_DEFINE_TYPE_WITH_PRIVATE(), but defines a final 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 lower case, with words
separated by `_` (snake case)
the #GType of the parent type
A convenience macro for defining flag types.
This macro will generate a `*_get_type()` function for the
given @TypeName, using @type_name as the function prefix.
|[<!-- language="C" -->
G_DEFINE_FLAGS_TYPE (GSettingsBindFlags, g_settings_bind_flags,
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_DEFAULT, "default"),
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_GET, "get"),
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_SET, "set"),
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_NO_SENSITIVITY, "no-sensitivity"),
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_GET_NO_CHANGES, "get-no-changes"),
G_DEFINE_ENUM_VALUE (G_SETTINGS_BIND_INVERT_BOOLEAN, "invert-boolean"))
]|
For projects that have multiple enumeration types, or enumeration
types with many values, you should consider using glib-mkenums to
generate the type function.
the enumeration type, in `CamelCase`
the enumeration type prefixed, in `snake_case`
a list of enumeration values, defined using G_DEFINE_ENUM_VALUE()
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 %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 %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
A convenience macro for 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()` function.
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.
The most general convenience macro for type implementations, on which
G_DEFINE_TYPE(), etc are based.
|[<!-- language="C" -->
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
|[<!-- language="C" -->
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 gsize static_g_define_type_id = 0;
if (g_once_init_enter (&static_g_define_type_id))
{
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 (&static_g_define_type_id, g_define_type_id);
}
return static_g_define_type_id;
}
]|
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.
A type for objects that have an initially floating reference.
All the fields in the `GInitiallyUnowned` structure are private to the
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
The base object type.
All the fields in the `GObject` structure are private to the implementation
and should never be accessed directly.
Since GLib 2.72, all #GObjects are guaranteed to be aligned to at least the
alignment of the largest basic GLib type (typically this is #guint64 or
#gdouble). If you need larger alignment for an element in a #GObject, you
should allocate it on the heap (aligned), or arrange for your #GObject to be
appropriately padded. This guarantee applies to the #GObject (or derived)
struct, the #GObjectClass (or derived) struct, and any private data allocated
by G_ADD_PRIVATE().
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.
Since GLib 2.72, all #GObjects are guaranteed to be aligned to at least the
alignment of the largest basic GLib type (typically this is #guint64 or
#gdouble). If you need larger alignment for an element in a #GObject, you
should allocate it on the heap (aligned), or arrange for your #GObject to be
appropriately padded.
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:
|[<!-- language="C" -->
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.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, @source and @target are only used from a single thread and it
is clear that both @source and @target outlive the binding. Especially it
is not safe to rely on this if the binding, @source or @target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
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, G_CONNECT_DEFAULT)
- object-signal, object_signal: equivalent to g_signal_connect_object (..., G_CONNECT_DEFAULT)
- 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)
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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
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
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.:
|[<!-- language="C" -->
typedef enum
{
PROP_FOO = 1,
PROP_LAST
} MyObjectProperty;
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_PARAM_STATIC_STRINGS);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
]|
and then notify a change on the "foo" property with:
|[<!-- language="C" -->
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, or %NULL to
match any toggle refs with the @notify argument.
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:
|[<!-- language="C" -->
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
If @object is floating, sink it. Otherwise, do nothing.
In other words, this function will convert a floating reference (if
present) into a full reference.
Typically you want to use g_object_ref_sink() in order to
automatically do the correct thing with respect to floating or
non-floating references, but there is one specific scenario where
this function is helpful.
The situation where this function is helpful is when creating an API
that allows the user to provide a callback function that returns a
GObject. We certainly want to allow the user the flexibility to
return a non-floating reference from this callback (for the case
where the object that is being returned already exists).
At the same time, the API style of some popular GObject-based
libraries (such as Gtk) make it likely that for newly-created GObject
instances, the user can be saved some typing if they are allowed to
return a floating reference.
Using this function on the return value of the user's callback allows
the user to do whichever is more convenient for them. The caller will
alway receives exactly one full reference to the value: either the
one that was returned in the first place, or a floating reference
that has been converted to a full reference.
This function has an odd interaction when combined with
g_object_ref_sink() running at the same time in another thread on
the same #GObject instance. If g_object_ref_sink() runs first then
the result will be that the floating reference is converted to a hard
reference. If g_object_take_ref() runs first then the result will be
that the floating reference is converted to a hard reference and an
additional reference on top of that one is added. It is best to avoid
this situation.
@object
a #GObject
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 disposed. 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:
|[<!-- language="C" -->
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.
|[<!-- language="C" -->
// 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:
|[<!-- language="C" -->
typedef enum {
PROP_FOO = 1,
PROP_BAR,
N_PROPERTIES
} MyObjectProperty;
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 | G_PARAM_STATIC_STRINGS);
obj_properties[PROP_BAR] =
g_param_spec_string ("bar", "Bar", "Bar",
NULL,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
gobject_class->set_property = my_object_set_property;
gobject_class->get_property = my_object_get_property;
g_object_class_install_properties (gobject_class,
G_N_ELEMENTS (obj_properties),
obj_properties);
}
]|
allows calling g_object_notify_by_pspec() to notify of property changes:
|[<!-- language="C" -->
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.
It is recommended to use this for all properties by default, as it allows for
internal performance improvements in GObject.
It is very rare that a property would have a dynamically constructed name,
nickname or 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, the
@nick and @blurb, which may be used as a localized label and description.
For GTK and related libraries these are considered deprecated and may be
omitted, while for other libraries such as GStreamer and its plugins they
are essential. When in doubt, follow the conventions used in the
surrounding code and supporting libraries.
(transfer floating): a newly allocated
#GParamSpec instance, which is initially floating
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
A #GParamSpec derived structure that redirects operations to
other types of #GParamSpec.
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 %TRUE will continue with
the signal emission. Returning %FALSE will abort the current emission.
Since 2.62, returning %FALSE will skip to the CLEANUP stage. In this case,
emission will occur as normal in the CLEANUP stage and the handler's
return value will be accumulated.
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.
Emission hooks allow 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.
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.
Only used in #GSignalAccumulator accumulator
functions for the #GSignalInvocationHint::run_type field to mark the first
call to the accumulator function for a signal emission. Since 2.68.
#GSignalGroup manages to simplify the process of connecting
many signals to a #GObject as a group. As such there is no API
to disconnect a signal from the group.
In particular, this allows you to:
- Change the target instance, which automatically causes disconnection
of the signals from the old instance and connecting to the new instance.
- Block and unblock signals as a group
- Ensuring that blocked state transfers across target instances.
One place you might want to use such a structure is with #GtkTextView and
#GtkTextBuffer. Often times, you'll need to connect to many signals on
#GtkTextBuffer from a #GtkTextView subclass. This allows you to create a
signal group during instance construction, simply bind the
#GtkTextView:buffer property to #GSignalGroup:target and connect
all the signals you need. When the #GtkTextView:buffer property changes
all of the signals will be transitioned correctly.
Creates a new #GSignalGroup for target instances of @target_type.
a new #GSignalGroup
the #GType of the target instance.
Blocks all signal handlers managed by @self so they will not
be called during any signal emissions. Must be unblocked exactly
the same number of times it has been blocked to become active again.
This blocked state will be kept across changes of the target instance.
the #GSignalGroup
Connects @c_handler to the signal @detailed_signal
on the target instance of @self.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form "signal-name::detail"
the #GCallback to connect
the data to pass to @c_handler calls
Connects @c_handler to the signal @detailed_signal
on the target instance of @self.
The @c_handler will be called after the default handler of the signal.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form "signal-name::detail"
the #GCallback to connect
the data to pass to @c_handler calls
Connects @closure to the signal @detailed_signal on #GSignalGroup:target.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form `signal-name` with optional `::signal-detail`
the closure to connect.
whether the handler should be called before or after the
default handler of the signal.
Connects @c_handler to the signal @detailed_signal
on the target instance of @self.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form "signal-name::detail"
the #GCallback to connect
the data to pass to @c_handler calls
function to be called when disposing of @self
the flags used to create the signal connection
Connects @c_handler to the signal @detailed_signal on #GSignalGroup:target.
Ensures that the @object stays alive during the call to @c_handler
by temporarily adding a reference count. When the @object is destroyed
the signal handler will automatically be removed.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form `signal-name` with optional `::signal-detail`
the #GCallback to connect
the #GObject to pass as data to @c_handler calls
#GConnectFlags for the signal connection
Connects @c_handler to the signal @detailed_signal
on the target instance of @self.
The instance on which the signal is emitted and @data
will be swapped when calling @c_handler.
You cannot connect a signal handler after #GSignalGroup:target has been set.
a #GSignalGroup
a string of the form "signal-name::detail"
the #GCallback to connect
the data to pass to @c_handler calls
Gets the target instance used when connecting signals.
The target instance
the #GSignalGroup
Sets the target instance used when connecting signals. Any signal
that has been registered with g_signal_group_connect_object() or
similar functions will be connected to this object.
If the target instance was previously set, signals will be
disconnected from that object prior to connecting to @target.
the #GSignalGroup.
The target instance used
when connecting signals.
Unblocks all signal handlers managed by @self so they will be
called again during any signal emissions unless it is blocked
again. Must be unblocked exactly the same number of times it
has been blocked to become active again.
the #GSignalGroup
The target instance used when connecting signals.
The #GType of the target property.
This signal is emitted when #GSignalGroup:target is set to a new value
other than %NULL. It is similar to #GObject::notify on `target` except it
will not emit when #GSignalGroup:target is %NULL and also allows for
receiving the #GObject without a data-race.
a #GObject containing the new value for #GSignalGroup:target
This signal is emitted when the target instance of @self is set to a
new #GObject.
This signal will only be emitted if the previous target of @self is
non-%NULL.
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 and %G_SIGNAL_ACCUMULATOR_FIRST_RUN.
%G_SIGNAL_ACCUMULATOR_FIRST_RUN is only set for the first run of the accumulator
function for a signal emission.
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.
See also: g_signal_query()
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:
|[<!-- language="C" -->
@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 deprecated. Instantiating a deprecated type will
trigger a warning if running with `G_ENABLE_DIAGNOSTIC=1`.
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 if @type is a final type. A final type cannot be derived any
further.
a #GType value
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 also: 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().
|[<!-- language="C" -->
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.
No special flags. Since: 2.74
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()
Indicates a final type. A final type is a non-derivable
leaf node in a deep derivable type hierarchy tree. Since: 2.70
The type is deprecated and may be removed in a
future version. A warning will be emitted if it is instantiated while
running with `G_ENABLE_DIAGNOSTIC=1`. Since 2.76
Bit masks used to check or determine specific characteristics of a
fundamental type.
Indicates a classed type
Indicates an instantiatable 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 most specific instantiatable prerequisite of an
interface type. If the interface type has no instantiatable
prerequisite, %G_TYPE_INVALID is returned.
See g_type_interface_add_prerequisite() for more information
about prerequisites.
the instantiatable prerequisite type or %G_TYPE_INVALID if none
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
reference cannot be released from within the 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
An interface that handles the lifecycle of dynamically loaded types.
The GObject type system supports dynamic loading of 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:
|[<!-- language="C" -->
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 instantiatable 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 instantiatable 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.
See also: g_type_query()
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 a copy of @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 disposed 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.
In particular, this means it’s invalid to call g_object_ref(),
g_weak_ref_init(), g_weak_ref_set(), g_object_add_toggle_ref(),
g_object_weak_ref(), g_object_add_weak_pointer() or any function which calls
them on the object from this callback.
data that was provided when the weak reference was established
the object being disposed
A structure containing a weak reference to a #GObject.
A `GWeakRef` 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 (‘re-referencing’), any #GWeakRefs taken
before it was disposed will continue to point to %NULL. Any #GWeakRefs taken
during disposal and after re-referencing, or after disposal has returned due
to the re-referencing, will continue to point to the object until its refcount
goes back to zero, at which point they too will be invalidated.
It is invalid to take a #GWeakRef on an object during #GObjectClass.dispose
without first having or creating a strong reference to the object.
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.
For the general case, it is recommended to use G_DEFINE_BOXED_TYPE()
instead of calling g_boxed_type_register_static() directly. The macro
will create the appropriate `*_get_type()` function for the boxed 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
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
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
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
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.
There is also a macro version of this function so that the code
will be inlined.
A pointer to a handler ID (of type #gulong) of the handler to be disconnected.
The instance to remove the signal handler from.
This pointer may be %NULL or invalid, if the handler ID is zero.
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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. Before
destruction you must always use g_value_unset() to make sure allocated
memory is freed.
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.
|[<!-- language="C" -->
#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;
}
]|
See also [gobject-Standard-Parameter-and-Value-Types] for more information on
validation of #GValue.
For letting a #GValue own (and memory manage) arbitrary types or pointers,
they need to become a [boxed type][gboxed]. The example below shows how
the pointer `mystruct` of type `MyStruct` is used as a [boxed type][gboxed].
|[<!-- language="C" -->
typedef struct { ... } MyStruct;
G_DEFINE_BOXED_TYPE (MyStruct, my_struct, my_struct_copy, my_struct_free)
// These two lines normally go in a public header. By GObject convention,
// the naming scheme is NAMESPACE_TYPE_NAME:
#define MY_TYPE_STRUCT (my_struct_get_type ())
GType my_struct_get_type (void);
void
foo ()
{
GValue *value = g_new0 (GValue, 1);
g_value_init (value, MY_TYPE_STRUCT);
g_value_set_boxed (value, mystruct);
// [... your code ....]
g_value_unset (value);
g_value_free (value);
}
]|
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 [Instantiatable classed types:
Objects][gtype-instantiatable-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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
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:
|[<!-- language="C" -->
// 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.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecBoxed instance specifying a %G_TYPE_BOXED
derived property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
%G_TYPE_BOXED derived type of this property
flags for the property specified
Creates a new #GParamSpecChar instance specifying a %G_TYPE_CHAR property.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecDouble instance specifying a %G_TYPE_DOUBLE
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecEnum instance specifying a %G_TYPE_ENUM
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GType derived from %G_TYPE_ENUM
default value for the property specified
flags for the property specified
Creates a new #GParamSpecFlags instance specifying a %G_TYPE_FLAGS
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GType derived from %G_TYPE_FLAGS
default value for the property specified
flags for the property specified
Creates a new #GParamSpecFloat instance specifying a %G_TYPE_FLOAT property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecGType instance specifying a
%G_TYPE_GTYPE property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GType whose subtypes are allowed as values
of the property (use %G_TYPE_NONE for any type)
flags for the property specified
Creates a new #GParamSpecInt instance specifying a %G_TYPE_INT property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecInt64 instance specifying a %G_TYPE_INT64 property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecLong instance specifying a %G_TYPE_LONG property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecBoxed instance specifying a %G_TYPE_OBJECT
derived property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
%G_TYPE_OBJECT derived type of this property
flags for the property specified
Creates a new property of type #GParamSpecOverride. This is used
to direct operations to another paramspec, and will not be directly
useful unless you are implementing a new base type similar to GObject.
the newly created #GParamSpec
the name of the property.
The property that is being overridden
Creates a new #GParamSpecParam instance specifying a %G_TYPE_PARAM
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GType derived from %G_TYPE_PARAM
flags for the property specified
Creates a new #GParamSpecPointer instance specifying a pointer property.
Where possible, it is better to use g_param_spec_object() or
g_param_spec_boxed() to expose memory management information.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
flags for the property specified
Creates a new #GParamSpecString instance.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecUChar instance specifying a %G_TYPE_UCHAR property.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecUInt instance specifying a %G_TYPE_UINT property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecUInt64 instance specifying a %G_TYPE_UINT64
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecULong instance specifying a %G_TYPE_ULONG
property.
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
minimum value for the property specified
maximum value for the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecUnichar instance specifying a %G_TYPE_UINT
property. #GValue structures for this property can be accessed with
g_value_set_uint() and g_value_get_uint().
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
default value for the property specified
flags for the property specified
Creates a new #GParamSpecValueArray instance specifying a
%G_TYPE_VALUE_ARRAY property. %G_TYPE_VALUE_ARRAY is a
%G_TYPE_BOXED type, as such, #GValue structures for this property
can be accessed with g_value_set_boxed() and g_value_get_boxed().
See g_param_spec_internal() for details on property names.
a newly created parameter specification
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GParamSpec describing the elements contained in
arrays of this property, may be %NULL
flags for the property specified
Creates a new #GParamSpecVariant instance specifying a #GVariant
property.
If @default_value is floating, it is consumed.
See g_param_spec_internal() for details on property names.
the newly created #GParamSpec
canonical name of the property specified
nick name for the property specified
description of the property specified
a #GVariantType
a #GVariant of type @type to
use as the default value, or %NULL
flags for the property specified
Registers @name as the name of a new static type derived
from %G_TYPE_PARAM.
The type system uses the information contained in the #GParamSpecTypeInfo
structure pointed to by @info to manage the #GParamSpec type and its
instances.
The new type identifier.
0-terminated string used as the name of the new #GParamSpec type.
The #GParamSpecTypeInfo for this #GParamSpec type.
Transforms @src_value into @dest_value if possible, and then
validates @dest_value, in order for it to conform to @pspec. If
@strict_validation is %TRUE this function will only succeed if the
transformed @dest_value complied to @pspec without modifications.
See also g_value_type_transformable(), g_value_transform() and
g_param_value_validate().
%TRUE if transformation and validation were successful,
%FALSE otherwise and @dest_value is left untouched.
a valid #GParamSpec
source #GValue
destination #GValue of correct type for @pspec
%TRUE requires @dest_value to conform to @pspec
without modifications
Checks whether @value contains the default value as specified in @pspec.
whether @value contains the canonical default for this @pspec
a valid #GParamSpec
a #GValue of correct type for @pspec
Return whether the contents of @value comply with the specifications
set out by @pspec.
whether the contents of @value comply with the specifications
set out by @pspec.
a valid #GParamSpec
a #GValue of correct type for @pspec
Sets @value to its default value as specified in @pspec.
a valid #GParamSpec
a #GValue of correct type for @pspec; since 2.64, you
can also pass an empty #GValue, initialized with %G_VALUE_INIT
#GValue provides an abstract container structure which can be
copied, transformed and compared while holding a value of any
(derived) type, which is registered as a #GType with a
#GTypeValueTable in its #GTypeInfo structure. Parameter
specifications for most value types can be created as #GParamSpec
derived instances, to implement e.g. #GObject properties which
operate on #GValue containers.
Parameter names need to start with a letter (a-z or A-Z). Subsequent
characters can be letters, numbers or a '-'.
All other characters are replaced by a '-' during construction.
See also #GValue for more information.
Ensures that the contents of @value comply with the specifications
set out by @pspec. For example, a #GParamSpecInt might require
that integers stored in @value may not be smaller than -42 and not be
greater than +42. If @value contains an integer outside of this range,
it is modified accordingly, so the resulting value will fit into the
range -42 .. +42.
whether modifying @value was necessary to ensure validity
a valid #GParamSpec
a #GValue of correct type for @pspec
Compares @value1 with @value2 according to @pspec, and return -1, 0 or +1,
if @value1 is found to be less than, equal to or greater than @value2,
respectively.
-1, 0 or +1, for a less than, equal to or greater than result
a valid #GParamSpec
a #GValue of correct type for @pspec
a #GValue of correct type for @pspec
Creates a new %G_TYPE_POINTER derived type id for a new
pointer type with name @name.
a new %G_TYPE_POINTER derived type id for @name.
the name of the new pointer type.
Updates a #GObject pointer to refer to @new_object.
It increments the reference count of @new_object (if non-%NULL), decrements
the reference count of the current value of @object_ptr (if non-%NULL), and
assigns @new_object to @object_ptr. The assignment is not atomic.
@object_ptr must not be %NULL, but can point to a %NULL value.
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.
One convenient usage of this function is in implementing property setters:
|[
void
foo_set_bar (Foo *foo,
Bar *new_bar)
{
g_return_if_fail (IS_FOO (foo));
g_return_if_fail (new_bar == NULL || IS_BAR (new_bar));
if (g_set_object (&foo->bar, new_bar))
g_object_notify (foo, "bar");
}
]|
a pointer to a #GObject reference
a pointer to the new #GObject to
assign to @object_ptr, or %NULL to clear the pointer
Updates a pointer to weakly refer to @new_object.
It assigns @new_object to @weak_pointer_location and ensures
that @weak_pointer_location will automatically be set to %NULL
if @new_object gets destroyed. The assignment is not atomic.
The weak reference is not thread-safe, see g_object_add_weak_pointer()
for details.
The @weak_pointer_location argument must not be %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.
One convenient usage of this function is in implementing property setters:
|[
void
foo_set_bar (Foo *foo,
Bar *new_bar)
{
g_return_if_fail (IS_FOO (foo));
g_return_if_fail (new_bar == NULL || IS_BAR (new_bar));
if (g_set_weak_pointer (&foo->bar, new_bar))
g_object_notify (foo, "bar");
}
]|
the memory address of a pointer
a pointer to the new #GObject to
assign to it, or %NULL to clear the pointer
A predefined #GSignalAccumulator for signals intended to be used as a
hook for application code to provide a particular value. Usually
only one such value is desired and multiple handlers for the same
signal don't make much sense (except for the case of the default
handler defined in the class structure, in which case you will
usually want the signal connection to override the class handler).
This accumulator will use the return value from the first signal
handler that is run as the return value for the signal and not run
any further handlers (ie: the first handler "wins").
standard #GSignalAccumulator result
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
A predefined #GSignalAccumulator for signals that return a
boolean values. The behavior that this accumulator gives is
that a return of %TRUE stops the signal emission: no further
callbacks will be invoked, while a return of %FALSE allows
the emission to continue. The idea here is that a %TRUE return
indicates that the callback handled the signal, and no further
handling is needed.
standard #GSignalAccumulator result
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
standard #GSignalAccumulator parameter
Adds an emission hook for a signal, which will get called for any emission
of that signal, independent of the instance. This is possible only
for signals which don't have %G_SIGNAL_NO_HOOKS flag set.
the hook id, for later use with g_signal_remove_emission_hook().
the signal identifier, as returned by g_signal_lookup().
the detail on which to call the hook.
a #GSignalEmissionHook function.
user data for @hook_func.
a #GDestroyNotify for @hook_data.
Calls the original class closure of a signal. This function should only
be called from an overridden class closure; see
g_signal_override_class_closure() and
g_signal_override_class_handler().
the argument list of the signal emission.
The first element in the array is a #GValue for the instance the signal
is being emitted on. The rest are any arguments to be passed to the signal.
Location for the return value.
Calls the original class closure of a signal. This function should
only be called from an overridden class closure; see
g_signal_override_class_closure() and
g_signal_override_class_handler().
the instance the signal is being
emitted on.
parameters to be passed to the parent class closure, followed by a
location for the return value. If the return type of the signal
is %G_TYPE_NONE, the return value location can be omitted.
Connects a #GCallback function to a signal for a particular object.
The handler will be called synchronously, before the default handler of the signal. g_signal_emit() will not return control until all handlers are called.
See [memory management of signal handlers][signal-memory-management] for
details on how to handle the return value and memory management of @data.
the instance to connect to.
a string of the form "signal-name::detail".
the #GCallback to connect.
data to pass to @c_handler calls.
Connects a #GCallback function to a signal for a particular object.
The handler will be called synchronously, after the default handler of the signal.
the instance to connect to.
a string of the form "signal-name::detail".
the #GCallback to connect.
data to pass to @c_handler calls.
Connects a closure to a signal for a particular object.
the handler ID (always greater than 0 for successful connections)
the instance to connect to.
a string of the form "signal-name::detail".
the closure to connect.
whether the handler should be called before or after the
default handler of the signal.
Connects a closure to a signal for a particular object.
the handler ID (always greater than 0 for successful connections)
the instance to connect to.
the id of the signal.
the detail.
the closure to connect.
whether the handler should be called before or after the
default handler of the signal.
Connects a #GCallback function to a signal for a particular object. Similar
to g_signal_connect(), but allows to provide a #GClosureNotify for the data
which will be called when the signal handler is disconnected and no longer
used. Specify @connect_flags if you need `..._after()` or
`..._swapped()` variants of this function.
the handler ID (always greater than 0 for successful connections)
the instance to connect to.
a string of the form "signal-name::detail".
the #GCallback to connect.
data to pass to @c_handler calls.
a #GClosureNotify for @data.
a combination of #GConnectFlags.
This is similar to g_signal_connect_data(), but uses a closure which
ensures that the @gobject stays alive during the call to @c_handler
by temporarily adding a reference count to @gobject.
When the @gobject is destroyed the signal handler will be automatically
disconnected. Note that this is not currently threadsafe (ie:
emitting a signal while @gobject is being destroyed in another thread
is not safe).
the handler id.
the instance to connect to.
a string of the form "signal-name::detail".
the #GCallback to connect.
the object to pass as data
to @c_handler.
a combination of #GConnectFlags.
Connects a #GCallback function to a signal for a particular object.
The instance on which the signal is emitted and @data will be swapped when
calling the handler. This is useful when calling pre-existing functions to
operate purely on the @data, rather than the @instance: swapping the
parameters avoids the need to write a wrapper function.
For example, this allows the shorter code:
|[<!-- language="C" -->
g_signal_connect_swapped (button, "clicked",
(GCallback) gtk_widget_hide, other_widget);
]|
Rather than the cumbersome:
|[<!-- language="C" -->
static void
button_clicked_cb (GtkButton *button, GtkWidget *other_widget)
{
gtk_widget_hide (other_widget);
}
...
g_signal_connect (button, "clicked",
(GCallback) button_clicked_cb, other_widget);
]|
the instance to connect to.
a string of the form "signal-name::detail".
the #GCallback to connect.
data to pass to @c_handler calls.
Emits a signal. Signal emission is done synchronously.
The method will only return control after all handlers are called or signal emission was stopped.
Note that g_signal_emit() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
the instance the signal is being emitted on.
the signal id
the detail
parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is %G_TYPE_NONE, the return value location can be omitted.
Emits a signal. Signal emission is done synchronously.
The method will only return control after all handlers are called or signal emission was stopped.
Note that g_signal_emit_by_name() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
the instance the signal is being emitted on.
a string of the form "signal-name::detail".
parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is %G_TYPE_NONE, the return value location can be omitted. The
number of parameters to pass to this function is defined when creating the signal.
Emits a signal. Signal emission is done synchronously.
The method will only return control after all handlers are called or signal emission was stopped.
Note that g_signal_emit_valist() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
the instance the signal is being
emitted on.
the signal id
the detail
a list of parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is %G_TYPE_NONE, the return value location can be omitted.
Emits a signal. Signal emission is done synchronously.
The method will only return control after all handlers are called or signal emission was stopped.
Note that g_signal_emitv() doesn't change @return_value if no handlers are
connected, in contrast to g_signal_emit() and g_signal_emit_valist().
argument list for the signal emission.
The first element in the array is a #GValue for the instance the signal
is being emitted on. The rest are any arguments to be passed to the signal.
the signal id
the detail
Location to
store the return value of the signal emission. This must be provided if the
specified signal returns a value, but may be ignored otherwise.
Returns the invocation hint of the innermost signal emission of instance.
the invocation hint of the innermost
signal emission, or %NULL if not found.
the instance to query
Blocks a handler of an instance so it will not be called during any
signal emissions unless it is unblocked again. Thus "blocking" a
signal handler means to temporarily deactivate it, a signal handler
has to be unblocked exactly the same amount of times it has been
blocked before to become active again.
The @handler_id has to be a valid signal handler id, connected to a
signal of @instance.
The instance to block the signal handler of.
Handler id of the handler to be blocked.
Disconnects a handler from an 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 becomes invalid and may be reused.
The @handler_id has to be a valid signal handler id, connected to a
signal of @instance.
The instance to remove the signal handler from.
Handler id of the handler to be disconnected.
Finds the first signal handler that matches certain selection criteria.
The criteria mask is passed as an OR-ed combination of #GSignalMatchType
flags, and the criteria values are passed as arguments.
The match @mask has to be non-0 for successful matches.
If no handler was found, 0 is returned.
A valid non-0 signal handler id for a successful match.
The instance owning the signal handler to be found.
Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handler has to match.
Signal the handler has to be connected to.
Signal detail the handler has to be connected to.
The closure the handler will invoke.
The C closure callback of the handler (useless for non-C closures).
The closure data of the handler's closure.
Returns whether @handler_id is the ID of a handler connected to @instance.
whether @handler_id identifies a handler connected to @instance.
The instance where a signal handler is sought.
the handler ID.
Undoes the effect of a previous g_signal_handler_block() call. A
blocked handler is skipped during signal emissions and will not be
invoked, unblocking it (for exactly the amount of times it has been
blocked before) reverts its "blocked" state, so the handler will be
recognized by the signal system and is called upon future or
currently ongoing signal emissions (since the order in which
handlers are called during signal emissions is deterministic,
whether the unblocked handler in question is called as part of a
currently ongoing emission depends on how far that emission has
proceeded yet).
The @handler_id has to be a valid id of a signal handler that is
connected to a signal of @instance and is currently blocked.
The instance to unblock the signal handler of.
Handler id of the handler to be unblocked.
Blocks all handlers on an instance that match @func and @data.
The instance to block handlers from.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Blocks all handlers on an instance that match a certain selection criteria.
The criteria mask is passed as an OR-ed combination of #GSignalMatchType
flags, and the criteria values are passed as arguments.
Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
If no handlers were found, 0 is returned, the number of blocked handlers
otherwise.
The number of handlers that matched.
The instance to block handlers from.
Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
Signal the handlers have to be connected to.
Signal detail the handlers have to be connected to.
The closure the handlers will invoke.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Destroy all signal handlers of a type instance. This function is
an implementation detail of the #GObject dispose implementation,
and should not be used outside of the type system.
The instance whose signal handlers are destroyed
Disconnects all handlers on an instance that match @data.
The instance to remove handlers from
the closure data of the handlers' closures
Disconnects all handlers on an instance that match @func and @data.
The instance to remove handlers from.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Disconnects all handlers on an instance that match a certain
selection criteria. The criteria mask is passed as an OR-ed
combination of #GSignalMatchType flags, and the criteria values are
passed as arguments. Passing at least one of the
%G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC or
%G_SIGNAL_MATCH_DATA match flags is required for successful
matches. If no handlers were found, 0 is returned, the number of
disconnected handlers otherwise.
The number of handlers that matched.
The instance to remove handlers from.
Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
Signal the handlers have to be connected to.
Signal detail the handlers have to be connected to.
The closure the handlers will invoke.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Unblocks all handlers on an instance that match @func and @data.
The instance to unblock handlers from.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Unblocks all handlers on an instance that match a certain selection
criteria. The criteria mask is passed as an OR-ed combination of
#GSignalMatchType flags, and the criteria values are passed as arguments.
Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
If no handlers were found, 0 is returned, the number of unblocked handlers
otherwise. The match criteria should not apply to any handlers that are
not currently blocked.
The number of handlers that matched.
The instance to unblock handlers from.
Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
Signal the handlers have to be connected to.
Signal detail the handlers have to be connected to.
The closure the handlers will invoke.
The C closure callback of the handlers (useless for non-C closures).
The closure data of the handlers' closures.
Returns whether there are any handlers connected to @instance for the
given signal id and detail.
If @detail is 0 then it will only match handlers that were connected
without detail. If @detail is non-zero then it will match handlers
connected both without detail and with the given detail. This is
consistent with how a signal emitted with @detail would be delivered
to those handlers.
Since 2.46 this also checks for a non-default class closure being
installed, as this is basically always what you want.
One example of when you might use this is when the arguments to the
signal are difficult to compute. A class implementor may opt to not
emit the signal if no one is attached anyway, thus saving the cost
of building the arguments.
%TRUE if a handler is connected to the signal, %FALSE
otherwise.
the object whose signal handlers are sought.
the signal id.
the detail.
whether blocked handlers should count as match.
Validate a signal name. This can be useful for dynamically-generated signals
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. The rules for signal names are the same as those
for property names.
%TRUE if @name is a valid signal name, %FALSE otherwise.
the canonical name of the signal
Lists the signals by id that a certain instance or interface type
created. Further information about the signals can be acquired through
g_signal_query().
Newly allocated array of signal IDs.
Instance or interface type.
Location to store the number of signal ids for @itype.
Given the name of the signal and the type of object it connects to, gets
the signal's identifying integer. Emitting the signal by number is
somewhat faster than using the name each time.
Also tries the ancestors of the given type.
The type class passed as @itype must already have been instantiated (for
example, using g_type_class_ref()) for this function to work, as signals are
always installed during class initialization.
See g_signal_new() for details on allowed signal names.
the signal's identifying number, or 0 if no signal was found.
the signal's name.
the type that the signal operates on.
Given the signal's identifier, finds its name.
Two different signals may have the same name, if they have differing types.
the signal name, or %NULL if the signal number was invalid.
the signal's identifying number.
Creates a new signal. (This is usually done in the class initializer.)
A signal name consists of segments consisting of ASCII letters and
digits, separated by either the `-` or `_` character. The first
character of a signal name must be a letter. Names which violate these
rules lead to undefined behaviour. These are the same rules as for property
naming (see g_param_spec_internal()).
When registering a signal and looking up a signal, either separator can
be used, but they cannot be mixed. Using `-` is considerably more efficient.
Using `_` is discouraged.
If 0 is used for @class_offset subclasses cannot override the class handler
in their class_init method by doing super_class->signal_handler = my_signal_handler.
Instead they will have to use g_signal_override_class_handler().
If @c_marshaller is %NULL, g_cclosure_marshal_generic() will be used as
the marshaller for this signal. In some simple cases, g_signal_new()
will use a more optimized c_marshaller and va_marshaller for the signal
instead of g_cclosure_marshal_generic().
If @c_marshaller is non-%NULL, you need to also specify a va_marshaller
using g_signal_set_va_marshaller() or the generic va_marshaller will
be used.
the signal id
the name for the signal
the type this signal pertains to. It will also pertain to
types which are derived from this type.
a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
The offset of the function pointer in the class structure
for this type. Used to invoke a class method generically. Pass 0 to
not associate a class method slot with this signal.
the accumulator for this signal; may be %NULL.
user data for the @accumulator.
the function to translate arrays of parameter
values to signal emissions into C language callback invocations or %NULL.
the type of return value, or %G_TYPE_NONE for a signal
without a return value.
the number of parameter types to follow.
a list of types, one for each parameter.
Creates a new signal. (This is usually done in the class initializer.)
This is a variant of g_signal_new() that takes a C callback instead
of a class offset for the signal's class handler. This function
doesn't need a function pointer exposed in the class structure of
an object definition, instead the function pointer is passed
directly and can be overridden by derived classes with
g_signal_override_class_closure() or
g_signal_override_class_handler() and chained to with
g_signal_chain_from_overridden() or
g_signal_chain_from_overridden_handler().
See g_signal_new() for information about signal names.
If c_marshaller is %NULL, g_cclosure_marshal_generic() will be used as
the marshaller for this signal.
the signal id
the name for the signal
the type this signal pertains to. It will also pertain to
types which are derived from this type.
a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
a #GCallback which acts as class implementation of
this signal. Used to invoke a class method generically. Pass %NULL to
not associate a class method with this signal.
the accumulator for this signal; may be %NULL.
user data for the @accumulator.
the function to translate arrays of parameter
values to signal emissions into C language callback invocations or %NULL.
the type of return value, or %G_TYPE_NONE for a signal
without a return value.
the number of parameter types to follow.
a list of types, one for each parameter.
Creates a new signal. (This is usually done in the class initializer.)
See g_signal_new() for details on allowed signal names.
If c_marshaller is %NULL, g_cclosure_marshal_generic() will be used as
the marshaller for this signal.
the signal id
the name for the signal
the type this signal pertains to. It will also pertain to
types which are derived from this type.
a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
The closure to invoke on signal emission; may be %NULL.
the accumulator for this signal; may be %NULL.
user data for the @accumulator.
the function to translate arrays of parameter
values to signal emissions into C language callback invocations or %NULL.
the type of return value, or %G_TYPE_NONE for a signal
without a return value.
the number of parameter types in @args.
va_list of #GType, one for each parameter.
Creates a new signal. (This is usually done in the class initializer.)
See g_signal_new() for details on allowed signal names.
If c_marshaller is %NULL, g_cclosure_marshal_generic() will be used as
the marshaller for this signal.
the signal id
the name for the signal
the type this signal pertains to. It will also pertain to
types which are derived from this type
a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST
The closure to invoke on signal emission;
may be %NULL
the accumulator for this signal; may be %NULL
user data for the @accumulator
the function to translate arrays of
parameter values to signal emissions into C language callback
invocations or %NULL
the type of return value, or %G_TYPE_NONE for a signal
without a return value
the length of @param_types
an array of types, one for
each parameter (may be %NULL if @n_params is zero)
Overrides the class closure (i.e. the default handler) for the given signal
for emissions on instances of @instance_type. @instance_type must be derived
from the type to which the signal belongs.
See g_signal_chain_from_overridden() and
g_signal_chain_from_overridden_handler() for how to chain up to the
parent class closure from inside the overridden one.
the signal id
the instance type on which to override the class closure
for the signal.
the closure.
Overrides the class closure (i.e. the default handler) for the
given signal for emissions on instances of @instance_type with
callback @class_handler. @instance_type must be derived from the
type to which the signal belongs.
See g_signal_chain_from_overridden() and
g_signal_chain_from_overridden_handler() for how to chain up to the
parent class closure from inside the overridden one.
the name for the signal
the instance type on which to override the class handler
for the signal.
the handler.
Internal function to parse a signal name into its @signal_id
and @detail quark.
Whether the signal name could successfully be parsed and @signal_id_p and @detail_p contain valid return values.
a string of the form "signal-name::detail".
The interface/instance type that introduced "signal-name".
Location to store the signal id.
Location to store the detail quark.
%TRUE forces creation of a #GQuark for the detail.
Queries the signal system for in-depth information about a
specific signal. This function will fill in a user-provided
structure to hold signal-specific information. If an invalid
signal id is passed in, the @signal_id member of the #GSignalQuery
is 0. All members filled into the #GSignalQuery structure should
be considered constant and have to be left untouched.
The signal id of the signal to query information for.
A user provided structure that is
filled in with constant values upon success.
Deletes an emission hook.
the id of the signal
the id of the emission hook, as returned by
g_signal_add_emission_hook()
Change the #GSignalCVaMarshaller used for a given signal. This is a
specialised form of the marshaller that can often be used for the
common case of a single connected signal handler and avoids the
overhead of #GValue. Its use is optional.
the signal id
the instance type on which to set the marshaller.
the marshaller to set.
Stops a signal's current emission.
This will prevent the default method from running, if the signal was
%G_SIGNAL_RUN_LAST and you connected normally (i.e. without the "after"
flag).
Prints a warning if used on a signal which isn't being emitted.
the object whose signal handlers you wish to stop.
the signal identifier, as returned by g_signal_lookup().
the detail which the signal was emitted with.
Stops a signal's current emission.
This is just like g_signal_stop_emission() except it will look up the
signal id for you.
the object whose signal handlers you wish to stop.
a string of the form "signal-name::detail".
Creates a new closure which invokes the function found at the offset
@struct_offset in the class structure of the interface or classed type
identified by @itype.
a floating reference to a new #GCClosure
the #GType identifier of an interface or classed type
the offset of the member function of @itype's class
structure which is to be invoked by the new closure
The basic concept of the signal system is that of the emission
of a signal. Signals are introduced per-type and are identified
through strings. Signals introduced for a parent type are available
in derived types as well, so basically they are a per-type facility
that is inherited.
A signal emission mainly involves invocation of a certain set of
callbacks in precisely defined manner. There are two main categories
of such callbacks, per-object ones and user provided ones.
(Although signals can deal with any kind of instantiatable type, I'm
referring to those types as "object types" in the following, simply
because that is the context most users will encounter signals in.)
The per-object callbacks are most often referred to as "object method
handler" or "default (signal) handler", while user provided callbacks are
usually just called "signal handler".
The object method handler is provided at signal creation time (this most
frequently happens at the end of an object class' creation), while user
provided handlers are frequently connected and disconnected to/from a
certain signal on certain object instances.
A signal emission consists of five stages, unless prematurely stopped:
1. Invocation of the object method handler for %G_SIGNAL_RUN_FIRST signals
2. Invocation of normal user-provided signal handlers (where the @after
flag is not set)
3. Invocation of the object method handler for %G_SIGNAL_RUN_LAST signals
4. Invocation of user provided signal handlers (where the @after flag is set)
5. Invocation of the object method handler for %G_SIGNAL_RUN_CLEANUP signals
The user-provided signal handlers are called in the order they were
connected in.
All handlers may prematurely stop a signal emission, and any number of
handlers may be connected, disconnected, blocked or unblocked during
a signal emission.
There are certain criteria for skipping user handlers in stages 2 and 4
of a signal emission.
First, user handlers may be blocked. Blocked handlers are omitted during
callback invocation, to return from the blocked state, a handler has to
get unblocked exactly the same amount of times it has been blocked before.
Second, upon emission of a %G_SIGNAL_DETAILED signal, an additional
@detail argument passed in to g_signal_emit() has to match the detail
argument of the signal handler currently subject to invocation.
Specification of no detail argument for signal handlers (omission of the
detail part of the signal specification upon connection) serves as a
wildcard and matches any detail argument passed in to emission.
While the @detail argument is typically used to pass an object property name
(as with #GObject::notify), no specific format is mandated for the detail
string, other than that it must be non-empty.
## Memory management of signal handlers # {#signal-memory-management}
If you are connecting handlers to signals and using a #GObject instance as
your signal handler user data, you should remember to pair calls to
g_signal_connect() with calls to g_signal_handler_disconnect() or
g_signal_handlers_disconnect_by_func(). While signal handlers are
automatically disconnected when the object emitting the signal is finalised,
they are not automatically disconnected when the signal handler user data is
destroyed. If this user data is a #GObject instance, using it from a
signal handler after it has been finalised is an error.
There are two strategies for managing such user data. The first is to
disconnect the signal handler (using g_signal_handler_disconnect() or
g_signal_handlers_disconnect_by_func()) when the user data (object) is
finalised; this has to be implemented manually. For non-threaded programs,
g_signal_connect_object() can be used to implement this automatically.
Currently, however, it is unsafe to use in threaded programs.
The second is to hold a strong reference on the user data until after the
signal is disconnected for other reasons. This can be implemented
automatically using g_signal_connect_data().
The first approach is recommended, as the second approach can result in
effective memory leaks of the user data if the signal handler is never
disconnected for some reason.
Set the callback for a source as a #GClosure.
If the source is not one of the standard GLib types, the @closure_callback
and @closure_marshal fields of the #GSourceFuncs structure must have been
filled in with pointers to appropriate functions.
the source
a #GClosure
Sets a dummy callback for @source. The callback will do nothing, and
if the source expects a #gboolean return value, it will return %TRUE.
(If the source expects any other type of return value, it will return
a 0/%NULL value; whatever g_value_init() initializes a #GValue to for
that type.)
If the source is not one of the standard GLib types, the
@closure_callback and @closure_marshal fields of the #GSourceFuncs
structure must have been filled in with pointers to appropriate
functions.
the source
Return a newly allocated string, which describes the contents of a
#GValue. The main purpose of this function is to describe #GValue
contents for debugging output, the way in which the contents are
described may change between different GLib versions.
Newly allocated string.
#GValue which contents are to be described.
Adds a #GTypeClassCacheFunc to be called before the reference count of a
class goes from one to zero. This can be used to prevent premature class
destruction. All installed #GTypeClassCacheFunc functions will be chained
until one of them returns %TRUE. 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.
data to be passed to @cache_func
a #GTypeClassCacheFunc
Registers a private class structure for a classed type;
when the class is allocated, the private structures for
the class and all of its parent types are allocated
sequentially in the same memory block as the public
structures, and are zero-filled.
This function should be called in the
type's get_type() function after the type is registered.
The private structure can be retrieved using the
G_TYPE_CLASS_GET_PRIVATE() macro.
GType of a classed type
size of private structure
Adds a function to be called after an interface vtable is
initialized for any class (i.e. after the @interface_init
member of #GInterfaceInfo has been called).
This function is useful when you want to check an invariant
that depends on the interfaces of a class. For instance, the
implementation of #GObject uses this facility to check that an
object implements all of the properties that are defined on its
interfaces.
data to pass to @check_func
function to be called after each interface
is initialized
Adds @interface_type to the dynamic @instance_type. The information
contained in the #GTypePlugin structure pointed to by @plugin
is used to manage the relationship.
#GType value of an instantiatable type
#GType value of an interface type
#GTypePlugin structure to retrieve the #GInterfaceInfo from
Adds @interface_type to the static @instance_type.
The information contained in the #GInterfaceInfo structure
pointed to by @info is used to manage the relationship.
#GType value of an instantiatable type
#GType value of an interface type
#GInterfaceInfo structure for this
(@instance_type, @interface_type) combination
Private helper function to aid implementation of the
G_TYPE_CHECK_INSTANCE() macro.
%TRUE if @instance is valid, %FALSE otherwise
a valid #GTypeInstance structure
Return a newly allocated and 0-terminated array of type IDs, listing
the child types of @type.
Newly allocated
and 0-terminated array of child types, free with g_free()
the parent type
location to store the length of
the returned array, or %NULL
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
Creates and initializes an instance of @type if @type is valid and
can be instantiated. The type system only performs basic allocation
and structure setups for instances: actual instance creation should
happen through functions supplied by the type's fundamental type
implementation. So use of g_type_create_instance() is reserved for
implementers of fundamental types only. E.g. instances of the
#GObject hierarchy should be created via g_object_new() and never
directly through g_type_create_instance() which doesn't handle things
like singleton objects or object construction.
The extended members of the returned instance are guaranteed to be filled
with zeros.
Note: Do not use this function, unless you're implementing a
fundamental type. Also language bindings should not use this
function, but g_object_new() instead.
an allocated and initialized instance, subject to further
treatment by the fundamental type implementation
an instantiatable type to create an instance for
If the interface type @g_type is currently in use, returns its
default interface vtable.
the default
vtable for the interface, or %NULL if the type is not currently
in use
an interface type
Increments the reference count for the interface type @g_type,
and returns the default interface vtable for the type.
If the type is not currently in use, then the default vtable
for the type will be created and initialized by calling
the base interface init and default vtable init functions for
the type (the @base_init and @class_init members of #GTypeInfo).
Calling g_type_default_interface_ref() is useful when you
want to make sure that signals and properties for an interface
have been installed.
the default
vtable for the interface; call g_type_default_interface_unref()
when you are done using the interface.
an interface type
Decrements the reference count for the type corresponding to the
interface default vtable @g_iface. If the type is dynamic, then
when no one is using the interface and all references have
been released, the finalize function for the interface's default
vtable (the @class_finalize member of #GTypeInfo) will be called.
the default vtable
structure for an interface, as returned by g_type_default_interface_ref()
Returns the length of the ancestry of the passed in type. This
includes the type itself, so that e.g. a fundamental type has depth 1.
the depth of @type
a #GType
Ensures that the indicated @type has been registered with the
type system, and its _class_init() method has been run.
In theory, simply calling the type's _get_type() method (or using
the corresponding macro) is supposed take care of this. However,
_get_type() methods are often marked %G_GNUC_CONST for performance
reasons, even though this is technically incorrect (since
%G_GNUC_CONST requires that the function not have side effects,
which _get_type() methods do on the first call). As a result, if
you write a bare call to a _get_type() macro, it may get optimized
out by the compiler. Using g_type_ensure() guarantees that the
type's _get_type() method is called.
a #GType
Frees an instance of a type, returning it to the instance pool for
the type, if there is one.
Like g_type_create_instance(), this function is reserved for
implementors of fundamental types.
an instance of a type
Look up the type ID from a given type name, returning 0 if no type
has been registered under this name (this is the preferred method
to find out by name whether a specific type has been registered
yet).
corresponding type ID or 0
type name to look up
Internal function, used to extract the fundamental type ID portion.
Use G_TYPE_FUNDAMENTAL() instead.
fundamental type ID
valid type ID
Returns the next free fundamental type id which can be used to
register a new fundamental type with g_type_register_fundamental().
The returned type ID represents the highest currently registered
fundamental type identifier.
the next available fundamental type ID to be registered,
or 0 if the type system ran out of fundamental type IDs
Returns the number of instances allocated of the particular type;
this is only available if GLib is built with debugging support and
the instance_count debug flag is set (by setting the GOBJECT_DEBUG
variable to include instance-count).
the number of instances allocated of the given type;
if instance counts are not available, returns 0.
a #GType
Returns the #GTypePlugin structure for @type.
the corresponding plugin
if @type is a dynamic type, %NULL otherwise
#GType to retrieve the plugin for
Obtains data which has previously been attached to @type
with g_type_set_qdata().
Note that this does not take subtyping into account; data
attached to one type with g_type_set_qdata() cannot
be retrieved from a subtype using g_type_get_qdata().
the data, or %NULL if no data was found
a #GType
a #GQuark id to identify the data
Returns an opaque serial number that represents the state of the set
of registered types. Any time a type is registered this serial changes,
which means you can cache information based on type lookups (such as
g_type_from_name()) and know if the cache is still valid at a later
time by comparing the current serial with the one at the type lookup.
An unsigned int, representing the state of type registrations
This function used to initialise the type system. Since GLib 2.36,
the type system is initialised automatically and this function does
nothing.
the type system is now initialised automatically
This function used to initialise the type system with debugging
flags. Since GLib 2.36, the type system is initialised automatically
and this function does nothing.
If you need to enable debugging features, use the GOBJECT_DEBUG
environment variable.
the type system is now initialised automatically
bitwise combination of #GTypeDebugFlags values for
debugging purposes
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 most specific instantiatable prerequisite of an
interface type. If the interface type has no instantiatable
prerequisite, %G_TYPE_INVALID is returned.
See g_type_interface_add_prerequisite() for more information
about prerequisites.
the instantiatable prerequisite type or %G_TYPE_INVALID if none
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
Return a newly allocated and 0-terminated array of type IDs, listing
the interface types that @type conforms to.
Newly allocated
and 0-terminated array of interface types, free with g_free()
the type to list interface types for
location to store the length of
the returned array, or %NULL
If @is_a_type is a derivable type, check whether @type is a
descendant of @is_a_type. If @is_a_type is an interface, check
whether @type conforms to it.
%TRUE if @type is a @is_a_type
type to check ancestry for
possible ancestor of @type or interface that @type
could conform to
Get the unique name that is assigned to a type ID. Note that this
function (like all other GType API) cannot cope with invalid type
IDs. %G_TYPE_INVALID may be passed to this function, as may be any
other validly registered type ID, but randomized type IDs should
not be passed in and will most likely lead to a crash.
static type name or %NULL
type to return name for
Given a @leaf_type and a @root_type which is contained in its
ancestry, return the type that @root_type is the immediate parent
of. In other words, this function determines the type that is
derived directly from @root_type which is also a base class of
@leaf_type. Given a root type and a leaf type, this function can
be used to determine the types and order in which the leaf type is
descended from the root type.
immediate child of @root_type and ancestor of @leaf_type
descendant of @root_type and the type to be returned
immediate parent of the returned type
Return the direct parent type of the passed in type. If the passed
in type has no parent, i.e. is a fundamental type, 0 is returned.
the parent type
the derived type
Get the corresponding quark of the type IDs name.
the type names quark or 0
type to return quark of type name for
Queries the type system for information about a specific type.
This function will fill in a user-provided structure to hold
type-specific information. If an invalid #GType is passed in, the
@type member of the #GTypeQuery is 0. All members filled into the
#GTypeQuery structure should be considered constant and have to be
left untouched.
#GType of a static, classed type
a user provided structure that is
filled in with constant values upon success
Registers @type_name as the name of a new dynamic type derived from
@parent_type. The type system uses the information contained in the
#GTypePlugin structure pointed to by @plugin to manage the type and its
instances (if not abstract). The value of @flags determines the nature
(e.g. abstract or not) of the type.
the new type identifier or %G_TYPE_INVALID if registration failed
type from which this type will be derived
0-terminated string used as the name of the new type
#GTypePlugin structure to retrieve the #GTypeInfo from
bitwise combination of #GTypeFlags values
Registers @type_id as the predefined identifier and @type_name as the
name of a fundamental type. If @type_id is already registered, or a
type named @type_name is already registered, the behaviour is undefined.
The type system uses the information contained in the #GTypeInfo structure
pointed to by @info and the #GTypeFundamentalInfo structure pointed to by
@finfo to manage the type and its instances. The value of @flags determines
additional characteristics of the fundamental type.
the predefined type identifier
a predefined type identifier
0-terminated string used as the name of the new type
#GTypeInfo structure for this type
#GTypeFundamentalInfo structure for this type
bitwise combination of #GTypeFlags values
Registers @type_name as the name of a new static type derived from
@parent_type. The type system uses the information contained in the
#GTypeInfo structure pointed to by @info to manage the type and its
instances (if not abstract). The value of @flags determines the nature
(e.g. abstract or not) of the type.
the new type identifier
type from which this type will be derived
0-terminated string used as the name of the new type
#GTypeInfo structure for this type
bitwise combination of #GTypeFlags values
Registers @type_name as the name of a new static type derived from
@parent_type. The value of @flags determines the nature (e.g.
abstract or not) of the type. It works by filling a #GTypeInfo
struct and calling g_type_register_static().
the new type identifier
type from which this type will be derived
0-terminated string used as the name of the new type
size of the class structure (see #GTypeInfo)
location of the class initialization function (see #GTypeInfo)
size of the instance structure (see #GTypeInfo)
location of the instance initialization function (see #GTypeInfo)
bitwise combination of #GTypeFlags values
Removes a previously installed #GTypeClassCacheFunc. The cache
maintained by @cache_func has to be empty when calling
g_type_remove_class_cache_func() to avoid leaks.
data that was given when adding @cache_func
a #GTypeClassCacheFunc
Removes an interface check function added with
g_type_add_interface_check().
callback data passed to g_type_add_interface_check()
callback function passed to g_type_add_interface_check()
Attaches arbitrary data to a type.
a #GType
a #GQuark id to identify the data
the data
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
The prime purpose of a #GValueArray is for it to be used as an
object property that holds an array of values. A #GValueArray wraps
an array of #GValue elements in order for it to be used as a boxed
type through %G_TYPE_VALUE_ARRAY.
#GValueArray is deprecated in favour of #GArray since GLib 2.32. It
is possible to create a #GArray that behaves like a #GValueArray by
using the size of #GValue as the element size, and by setting
g_value_unset() as the clear function using g_array_set_clear_func(),
for instance, the following code:
|[<!-- language="C" -->
GValueArray *array = g_value_array_new (10);
]|
can be replaced by:
|[<!-- language="C" -->
GArray *array = g_array_sized_new (FALSE, TRUE, sizeof (GValue), 10);
g_array_set_clear_func (array, (GDestroyNotify) g_value_unset);
]|
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.