Interfacing Raku to Gnome GTK+


The GLib Runtime type identification and management system

Note: The methods described here are mostly used internally and is not of much interest for the normal Raku user.


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.

As mentioned in the 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 ‘-+’.



unit class Gnome::GObject::Type;

class N-GTypeQuery

A structure holding information for a specific type. It is filled in by the query() function.

  • UInt $.type: the GType value of the type.

  • Str $.type_name: the name of the type.

  • UInt $.class_size: the size of the class structure.

  • UInt $.instance_size: the size of the instance structure.



default, no options

Create a new plain object. In contrast with other objects, this class doesn’t wrap a native object, so therefore no options to specify something.


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.

method check-instance-cast (
  N-GObject $instance, UInt $iface_type --> N-GObject
  • N-GObject $instance;

  • UInt $iface_type;


Check if an instance is of type $iface-gtype. Returns True if it is.

method check-instance-is-a (
  N-GObject $instance, UInt $iface_gtype --> Bool
  • GTypeInstance $instance;

  • N-GObject $iface_type;


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.

Returns: the depth of $gtype

method depth ( UInt $gtype --> UInt )


Lookup 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).

Returns: corresponding type ID or 0

method from-name ( Str $name --> UInt )
  • Str $name; type name to lookup


Get dynamic type for a GTyped value. In C there is this name G_TYPE_GTYPE.

method gtype_get_type ( --> UInt )


If $is-a-gtype is a derivable type, check whether $gtype is a descendant of $is-a-gtype. If $is-a-gtype is an interface, check whether $gtype conforms to it.

Returns: True if $gtype is a $is-a-gtype

method is-a ( UInt $gtype, UInt $is_a_gtype --> Bool )
  • UInt $is_a_gtype; possible anchestor of $gtype or interface that $gtype 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.

Returns: static type name or undefined

method name ( UInt $gtype --> Str )


Get name of type from the instance.

method name-from-instance ( N-GObject $instance --> Str )
  • N-GObject $instance;


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.

Returns: the parent type

method parent ( UInt $parent-gtype --> UInt )


Get the corresponding quark of the type IDs name.

Returns: the type names quark or 0

method qname ( UInt $gtype --> UInt )


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 Gnome::GObject::Type is passed in, the $type member of the N-GTypeQuery is 0. All members filled into the N-GTypeQuery structure should be considered constant and have to be left untouched.

method query ( UInt $gtype --> N-GTypeQuery )