Glib::Object(3) User Contributed Perl Documentation Glib::Object(3)NAMEGlib::Object - Bindings for GObject
DESCRIPTION
GObject is the base object class provided by the gobject library. It
provides object properties with a notification system, and emittable
signals.
Glib::Object is the corresponding Perl object class. Glib::Objects are
represented by blessed hash references, with a magical connection to
the underlying C object.
get and set
Some subclasses of "Glib::Object" override "get" and "set" with methods
more useful to the subclass, for example "Gtk2::TreeModel" getting and
setting row contents.
This is usually done when the subclass has no object properties. Any
object properties it or a further subclass does have can always be
accessed with "get_property" and "set_property" (together with
"find_property" and "list_properties" to enquire about them).
Generic code for any object subclass can use the names "get_property"
and "set_property" to be sure of getting the object properties as such.
HIERARCHYGlib::ObjectMETHODS
object = $class->new (...)
· ... (list) key/value pairs, property values to set on creation
Instantiate a Glib::Object of type $class. Any key/value pairs in ...
are used to set properties on the new object; see "set". This is
designed to be inherited by Perl-derived subclasses (see
Glib::Object::Subclass), but you can actually use it to create any
GObject-derived type.
scalar = Glib::Object->new_from_pointer ($pointer, $noinc=FALSE)
· $pointer (unsigned) a C pointer value as an integer.
· $noinc (boolean) if true, do not increase the GObject's reference
count when creating the Perl wrapper. this typically means that
when the Perl wrapper will own the object. in general you don't
want to do that, so the default is false.
Create a Perl Glib::Object reference for the C object pointed to by
$pointer. You should need this very rarely; it's intended to support
foreign objects.
NOTE: the cast from arbitrary integer to GObject may result in a core
dump without warning, because the type-checking macro G_OBJECT()
attempts to dereference the pointer to find a GTypeClass structure, and
there is no portable way to validate the pointer.
unsigned = $object->get_data ($key)
· $key (string)
Fetch the integer stored under the object data key $key. These values
do not have types; type conversions must be done manually. See
"set_data".
$object->set_data ($key, $data)
· $key (string)
· $data (scalar)
GObject provides an arbitrary data mechanism that assigns unsigned
integers to key names. Functionality overlaps with the hash used as
the Perl object instance, so we strongly recommend you use hash keys
for your data storage. The GObject data values cannot store type
information, so they are not safe to use for anything but integer
values, and you really should use this method only if you know what you
are doing.
pspec or undef = $object_or_class_name->find_property ($name)
· $name (string)
Find the definition of object property $name for $object_or_class_name.
Return "undef" if no such property. For the returned data see
Glib::Object::list_properties.
$object->freeze_notify
Stops emission of "notify" signals on $object. The signals are queued
until "thaw_notify" is called on $object.
$object->get (...)
· ... (list) list of property names
Alias for "get_property" (see "get and set" above).
$object->set (key => $value, ...)
· ... (list) key/value pairs
Alias for "set_property" (see "get and set" above).
list = $object_or_class_name->list_properties
List all the object properties for $object_or_class_name; returns them
as a list of hashes, containing these keys:
name
The name of the property
type
The type of the property
owner_type
The type that owns the property
descr
The description of the property
flags
The Glib::ParamFlags of the property
$object->notify ($property_name)
· $property_name (string)
Emits a "notify" signal for the property $property on $object.
gpointer = $object->get_pointer
Complement of "new_from_pointer".
$object->get_property (...)
Fetch and return the values for the object properties named in ....
$object->set_property (key => $value, ...)
Set object properties.
unsigned = $object_or_class_name->signal_add_emission_hook
($detailed_signal, $hook_func, $hook_data=undef)
· $detailed_signal (string) of the form "signal-name::detail"
· $hook_func (subroutine)
· $hook_data (scalar)
Add an emission hook for a signal. The hook will be called for any
emission of that signal, independent of the instance. This is possible
only for signals which don't have the "G_SIGNAL_NO_HOOKS" flag set.
The $hook_func should be reference to a subroutine that looks something
like this:
sub emission_hook {
my ($invocation_hint, $parameters, $hook_data) = @_;
# $parameters is a reference to the @_ to be passed to
# signal handlers, including the instance as $parameters->[0].
return $stay_connected; # boolean
}
This function returns an id that can be used with
"remove_emission_hook".
Since 1.100.
list = $instance->signal_chain_from_overridden (...)
· ... (list)
Chain up to an overridden class closure; it is only valid to call this
from a class closure override.
Translation: because of various details in how GObjects are
implemented, the way to override a virtual method on a GObject is to
provide a new "class closure", or default handler for a signal. This
happens when a class is registered with the type system (see
Glib::Type::register and Glib::Object::Subclass). When called from
inside such an override, this method runs the overridden class closure.
This is equivalent to calling $self->SUPER::$method (@_) in normal Perl
objects.
unsigned = $instance->signal_connect ($detailed_signal, $callback,
$data=undef)
· $detailed_signal (string)
· $callback (subroutine)
· $data (scalar) arbitrary data to be passed to each invocation of
callback
Register callback to be called on each emission of $detailed_signal.
Returns an identifier that may be used to remove this handler with
"$object->signal_handler_disconnect".
unsigned = $instance->signal_connect_after ($detailed_signal, $callback,
$data=undef)
· $detailed_signal (string)
· $callback (scalar)
· $data (scalar)
Like "signal_connect", except that $callback will be run after the
default handler.
unsigned = $instance->signal_connect_swapped ($detailed_signal, $callback,
$data=undef)
· $detailed_signal (string)
· $callback (scalar)
· $data (scalar)
Like "signal_connect", except that $data and $object will be swapped on
invocation of $callback.
retval = $object->signal_emit ($name, ...)
· $name (string) the name of the signal
· ... (list) any arguments to pass to handlers.
Emit the signal name on $object. The number and types of additional
arguments in ... are determined by the signal; similarly, the presence
and type of return value depends on the signal being emitted.
$ihint = $instance->signal_get_invocation_hint
Get a reference to a hash describing the innermost signal currently
active on $instance. Returns undef if no signal emission is active.
This invocation hint is the same object passed to signal emission
hooks, and contains these keys:
signal_name
The name of the signal being emitted.
detail
The detail passed on for this emission. For example, a "notify"
signal will have the property name as the detail.
run_type
The current stage of signal emission, one of "run-first", "run-
last", or "run-cleanup".
$object->signal_handler_block ($handler_id)
· $handler_id (unsigned)
$object->signal_handler_disconnect ($handler_id)
· $handler_id (unsigned)
boolean = $object->signal_handler_is_connected ($handler_id)
· $handler_id (unsigned)
$object->signal_handler_unblock ($handler_id)
· $handler_id (unsigned)
integer = $instance->signal_handlers_block_by_func ($func, $data=undef)
· $func (subroutine) function to block
· $data (scalar) data to match, ignored if undef
integer = $instance->signal_handlers_disconnect_by_func ($func,
$data=undef)
· $func (subroutine) function to block
· $data (scalar) data to match, ignored if undef
integer = $instance->signal_handlers_unblock_by_func ($func, $data=undef)
· $func (subroutine) function to block
· $data (scalar) data to match, ignored if undef
scalar = $object_or_class_name->signal_query ($name)
· $name (string)
Look up information about the signal $name on the instance type
$object_or_class_name, which may be either a Glib::Object or a package
name.
See also "Glib::Type::list_signals", which returns the same kind of
hash refs as this does.
Since 1.080.
$object_or_class_name->signal_remove_emission_hook ($signal_name, $hook_id)
· $signal_name (string)
· $hook_id (unsigned)
Remove a hook that was installed by "add_emission_hook".
Since 1.100.
$instance->signal_stop_emission_by_name ($detailed_signal)
· $detailed_signal (string)
$object->thaw_notify
Reverts the effect of a previous call to "freeze_notify". This causes
all queued "notify" signals on $object to be emitted.
boolean = Glib::Object->set_threadsafe ($threadsafe)
· $threadsafe (boolean)
Enables/disables threadsafe gobject tracking. Returns whether or not
tracking will be successful and thus whether using perl ithreads will
be possible.
$object->tie_properties ($all=FALSE)
· $all (boolean) if FALSE (or omitted) tie only properties for this
object's class, if TRUE tie the properties of this and all parent
classes.
A special method avaiable to Glib::Object derivatives, it uses perl's
tie facilities to associate hash keys with the properties of the
object. For example:
$button->tie_properties;
# equivilent to $button->set (label => 'Hello World');
$button->{label} = 'Hello World';
print "the label is: ".$button->{label}."\n";
Attempts to write to read-only properties will croak, reading a write-
only property will return '[write-only]'.
Care must be taken when using tie_properties with objects of types
created with Glib::Object::Subclass as there may be clashes with
existing hash keys that could cause infinite loops. The solution is to
use custom property get/set functions to alter the storage locations of
the properties.
SIGNALS
notify (Glib::Object, Glib::ParamSpec)
ENUMS AND FLAGS
flags Glib::SignalFlags
· 'run-first' / 'G_SIGNAL_RUN_FIRST'
· 'run-last' / 'G_SIGNAL_RUN_LAST'
· 'run-cleanup' / 'G_SIGNAL_RUN_CLEANUP'
· 'no-recurse' / 'G_SIGNAL_NO_RECURSE'
· 'detailed' / 'G_SIGNAL_DETAILED'
· 'action' / 'G_SIGNAL_ACTION'
· 'no-hooks' / 'G_SIGNAL_NO_HOOKS'
SEE ALSO
Glib
COPYRIGHT
Copyright (C) 2003-2011 by the gtk2-perl team.
This software is licensed under the LGPL. See Glib for a full notice.
perl v5.14.2 2012-01-14 Glib::Object(3)