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/src/wrappers/gobject/library/g_type.e

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   1indexing
   2	description: "GType - the GLib Runtime type identification and management system."
   3	copyright: "(C) 2006 Paolo Redaelli "
   4	license: "LGPL v2 or later"
   5	date: "$Date:$"
   6	revision: "$Revision:$"
   7
   8			-- Description
   9			
  10			-- The GType API is the foundation of the GObject system. It
  11			-- provides the facilities for registering and managing all
  12			-- fundamental data types, user-defined object and interface
  13			-- types. Before using any GType or GObject functions,
  14			-- g_type_init() must be called to initialize the type
  15			-- system.
  16			
  17			-- For type creation and registration purposes, all types
  18			-- fall into one of two categories: static or dynamic. Static
  19			-- types are never loaded or unloaded at run-time as dynamic
  20			-- types may be. Static types are created with
  21			-- g_type_register_static() that gets type specific
  22			-- information passed in via a GTypeInfo structure. Dynamic
  23			-- types are created with g_type_register_dynamic() which
  24			-- takes a GTypePlugin structure instead. The remaining type
  25			-- information (the GTypeInfo structure) is retrieved during
  26			-- runtime through GTypePlugin and the g_type_plugin_*()
  27			-- API. These registration functions are usually called only
  28			-- once from a function whose only purpose is to return the
  29			-- type identifier for a specific class. Once the type (or
  30			-- class or interface) is registered, it may be instantiated,
  31			-- inherited, or implemented depending on exactly what sort
  32			-- of type it is. There is also a third registration function
  33			-- for registering fundamental types called
  34			-- g_type_register_fundamental() which requires both a
  35			-- GTypeInfo structure and a GTypeFundamentalInfo structure
  36			-- but it is seldom used since most fundamental types are
  37			-- predefined rather than user-defined.
  38
  39			-- A final word about type names. Such an identifier needs to
  40			-- be at least three characters long. There is no upper
  41			-- length limit. The first character needs to be a letter
  42			-- (a-z or A-Z) or an underscore '_'. Subsequent characters
  43			-- can be letters, numbers or any of '-_+'.
  44
  45deferred class G_TYPE
  46
  47insert G_TYPE_EXTERNALS
  48
  49feature
  50	-- Note: in libglib 2.9.1 "typedef gulong GType;" (Paolo
  51	-- 2006-01-07)
  52
  53	is_g_type (a_type_number: INTEGER): BOOLEAN is
  54			-- Is `a_type_number' a valid value for a g_type? (i.e. a
  55			-- type number that can be used for g_value_init()?
  56		do
  57			Result := (g_type_is_value_type (a_type_number)).to_boolean
  58		end
  59
  60
  61-- #define G_TYPE_FUNDAMENTAL(type)	(g_type_fundamental (type))
  62
  63-- Returns the fundamental type which is the ancestor of type. Fundamental types are types that serve as fundaments for the derived types, thus they are the roots of distinct inheritance hierarchies.
  64-- type : 	A GType value.
  65-- G_TYPE_MAKE_FUNDAMENTAL()
  66
  67-- #define	G_TYPE_MAKE_FUNDAMENTAL(x)	((GType) ((x) << G_TYPE_FUNDAMENTAL_SHIFT))
  68
  69-- Returns the type ID for the fundamental type number x. Use g_type_fundamental_next() instead of this macro to create new fundamental types.
  70-- x : 	the fundamental type number.
  71-- G_TYPE_IS_ABSTRACT()
  72
  73-- #define G_TYPE_IS_ABSTRACT(type)                (g_type_test_flags ((type), G_TYPE_FLAG_ABSTRACT))
  74
  75-- Returns TRUE if type is an abstract type. An abstract type can not be instantiated and is normally used as an abstract base class for derived classes.
  76-- type : 	A GType value.
  77-- G_TYPE_IS_DERIVED()
  78
  79-- #define G_TYPE_IS_DERIVED(type)                 ((type) > G_TYPE_FUNDAMENTAL_MAX)
  80
  81-- Returns TRUE if type is derived (or in object-oriented terminology: inherited) from another type (this holds true for all non-fundamental types).
  82-- type : 	A GType value.
  83-- G_TYPE_IS_FUNDAMENTAL()
  84
  85-- #define G_TYPE_IS_FUNDAMENTAL(type)             ((type) <= G_TYPE_FUNDAMENTAL_MAX)
  86
  87-- Returns TRUE if type is a fundamental type.
  88-- type : 	A GType value.
  89-- G_TYPE_IS_VALUE_TYPE()
  90
  91-- #define G_TYPE_IS_VALUE_TYPE(type)              (g_type_check_is_value_type (type))
  92
  93-- Returns TRUE if type is a value type which can be used for g_value_init().
  94-- type : 	A GType value.
  95-- G_TYPE_HAS_VALUE_TABLE()
  96
  97-- #define G_TYPE_HAS_VALUE_TABLE(type)            (g_type_value_table_peek (type) != NULL)
  98
  99-- Returns TRUE if type has a GTypeValueTable.
 100-- type : 	A GType value.
 101-- G_TYPE_IS_CLASSED()
 102
 103-- #define G_TYPE_IS_CLASSED(type)                 (g_type_test_flags ((type), G_TYPE_FLAG_CLASSED))
 104
 105-- Returns TRUE if type is a classed type.
 106-- type : 	A GType value.
 107-- G_TYPE_IS_INSTANTIATABLE()
 108
 109-- #define G_TYPE_IS_INSTANTIATABLE(type)          (g_type_test_flags ((type), G_TYPE_FLAG_INSTANTIATABLE))
 110
 111-- Returns TRUE if type can be instantiated. Instantiation is the process of creating an instance (object) of this type.
 112-- type : 	A GType value.
 113-- G_TYPE_IS_DERIVABLE()
 114
 115-- #define G_TYPE_IS_DERIVABLE(type)               (g_type_test_flags ((type), G_TYPE_FLAG_DERIVABLE))
 116
 117-- Returns TRUE if type is a derivable type. A derivable type can be used as the base class of a flat (single-level) class hierarchy.
 118-- type : 	A GType value.
 119-- G_TYPE_IS_DEEP_DERIVABLE()
 120
 121-- #define G_TYPE_IS_DEEP_DERIVABLE(type)          (g_type_test_flags ((type), G_TYPE_FLAG_DEEP_DERIVABLE))
 122
 123-- Returns TRUE 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.
 124-- type : 	A GType value.
 125-- G_TYPE_IS_INTERFACE()
 126
 127-- #define G_TYPE_IS_INTERFACE(type)               (G_TYPE_FUNDAMENTAL (type) == G_TYPE_INTERFACE)
 128
 129-- Returns TRUE if type is an interface type. Interface types are types that provide pure APIs, 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).
 130-- type : 	A GType value.
 131-- GTypeInterface
 132
 133-- typedef struct {
 134-- } GTypeInterface;
 135
 136-- An opaque structure used as the base of all interface types.
 137-- GTypeInstance
 138
 139-- typedef struct {
 140-- } GTypeInstance;
 141
 142-- An opaque structure used as the base of all type instances.
 143-- GTypeClass
 144
 145-- typedef struct {
 146-- } GTypeClass;
 147
 148-- An opaque structure used as the base of all classes.
 149-- GTypeInfo
 150
 151-- typedef struct {
 152--   /* interface types, classed types, instantiated types */
 153--   guint16                class_size;
 154
 155--   GBaseInitFunc          base_init;
 156--   GBaseFinalizeFunc      base_finalize;
 157
 158--   /* interface types, classed types, instantiated types */
 159--   GClassInitFunc         class_init;
 160--   GClassFinalizeFunc     class_finalize;
 161--   gconstpointer          class_data;
 162
 163--   /* instantiated types */
 164--   guint16                instance_size;
 165--   guint16                n_preallocs;
 166--   GInstanceInitFunc      instance_init;
 167
 168--   /* value handling */
 169--   const GTypeValueTable	*value_table;
 170-- } GTypeInfo;
 171
 172-- This structure is used to provide the type system with the information required to initialize and destruct (finalize) a type's class and instances thereof. 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 it's memory does not need to be persistent across invocation of g_type_register_static().
 173-- guint16 class_size; 	Size of the class structure (required for interface, classed and instantiatable types).
 174-- GBaseInitFunc base_init; 	Location of the base initialization function (optional).
 175-- GBaseFinalizeFunc base_finalize; 	Location of the base finalization function (optional).
 176-- GClassInitFunc class_init; 	Location of the class initialization function for classed and 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.
 177-- GClassFinalizeFunc class_finalize; 	Location of the class finalization function for classed and types. Location fo the default vtable finalization function for interface types. (optional)
 178-- gconstpointer class_data; 	User-supplied data passed to the class init/finalize functions.
 179-- guint16 instance_size; 	Size of the instance (object) structure (required for instantiatable types only).
 180-- guint16 n_preallocs; 	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 now.
 181-- GInstanceInitFunc instance_init; 	Location of the instance initialization function (optional, for instantiatable types only).
 182-- const GTypeValueTable *value_table; 	A GTypeValueTable function table for generic handling of GValues of this type (usually only useful for fundamental types).
 183-- GTypeFundamentalInfo
 184
 185-- typedef struct {
 186--   GTypeFundamentalFlags  type_flags;
 187-- } GTypeFundamentalInfo;
 188
 189-- A structure that provides information to the type system which is used specifically for managing fundamental types.
 190-- GTypeFundamentalFlags type_flags; 	GTypeFundamentalFlags describing the characteristics of the fundamental type
 191-- GInterfaceInfo
 192
 193-- typedef struct {
 194--   GInterfaceInitFunc     interface_init;
 195--   GInterfaceFinalizeFunc interface_finalize;
 196--   gpointer               interface_data;
 197-- } GInterfaceInfo;
 198
 199-- A structure that provides information to the type system which is used specifically for managing interface types.
 200-- GTypeValueTable
 201
 202-- typedef struct {
 203--   void     (*value_init)         (GValue       *value);
 204--   void     (*value_free)         (GValue       *value);
 205--   void     (*value_copy)         (const GValue *src_value,
 206-- 				  GValue       *dest_value);
 207--   /* varargs functionality (optional) */
 208--   gpointer (*value_peek_pointer) (const GValue *value);
 209--   gchar	    *collect_format;
 210--   gchar*   (*collect_value)      (GValue       *value,
 211-- 				  guint         n_collect_values,
 212-- 				  GTypeCValue  *collect_values,
 213-- 				  guint		collect_flags);
 214--   gchar	    *lcopy_format;
 215--   gchar*   (*lcopy_value)        (const GValue *value,
 216-- 				  guint         n_collect_values,
 217-- 				  GTypeCValue  *collect_values,
 218-- 				  guint		collect_flags);
 219-- } GTypeValueTable;
 220
 221-- The GTypeValueTable provides the functions required by the GValue implementation, to serve as a container for values of a type.
 222-- value_init () 	Default initialize values contents by poking values directly into the value->data array. The data array of the GValue passed into this function was zero-filled with memset(), so no care has to be taken to free any old contents. E.g. for the implementation of a string value that may never be NULL, the implementation might look like:
 223
 224-- {
 225--   value->data[0].v_pointer = g_strdup ("");
 226-- }
 227
 228-- value_free () 	Free any old contents that might be left in the data array of the passed in value. No resources may remain allocated through the GValue contents after this function returns. E.g. for our above string type:
 229
 230-- {
 231--   /* only free strings without a specific flag for static storage */
 232--   if (!(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
 233--     g_free (value->data[0].v_pointer);
 234-- }
 235
 236-- value_copy () 	dest_value is a GValue with zero-filled data section and src_value is a properly setup GValue of same or derived type. The purpose of this function is to copy the contents of src_value into dest_value in a way, that even after src_value has been freed, the contents of dest_value remain valid. String type example:
 237
 238-- {
 239--   dest_value->data[0].v_pointer = g_strdup (src_value->data[0].v_pointer);
 240-- }
 241
 242-- value_peek_pointer () 	If the value contents fit into a pointer, such as objects or strings, return this pointer, so the caller can peek at the current contents. To extend on our above string example:
 243
 244-- {
 245--   return value->data[0].v_pointer;
 246-- }
 247
 248-- gchar *collect_format; 	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, the characters themselves indicate the type of the argument. Currently supported arguments are:
 249
 250-- 'i' - Integers. passed as collect_values[].v_int.
 251
 252-- 'l' - Longs. passed as collect_values[].v_long.
 253
 254-- 'd' - Doubles. passed as collect_values[].v_double.
 255
 256-- 'p' - Pointers. passed as collect_values[].v_pointer.
 257-- 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'.
 258-- collect_value () 	The collect_value() function is responsible for converting the values collected from a variable argument list into contents suitable for storage in a GValue. This function should setup value similar to value_init(), e.g. for a string value that does not allow NULL pointers, it needs to either spew an error, or do an implicit conversion by storing an empty string. The value passed in to this function has a zero-filled data array, so just like for value_init() it is guaranteed to not contain any old contents that might need freeing. n_collect_values is exactly the string length of collect_format, and collect_values is an array of unions GTypeCValue with length n_collect_values, containing the collected values according to collect_format. collect_flags is an argument provided as a hint by the caller, which may contain the flag G_VALUE_NOCOPY_CONTENTS indicating, that the collected value contents may be considered "static" for the duration of the value lifetime. Thus an extra copy of the contents stored in collect_values is not required for assignment to value. For our above string example, we continue with:
 259
 260-- {
 261--   if (!collect_values[0].v_pointer)
 262--     value->data[0].v_pointer = g_strdup ("");
 263--   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 264--     {
 265--       value->data[0].v_pointer = collect_values[0].v_pointer;
 266--       /* keep a flag for the value_free() implementation to not free this string */
 267--       value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
 268--     }
 269--   else
 270--     value->data[0].v_pointer = g_strdup (collect_values[0].v_pointer);
 271
 272--   return NULL;
 273-- }
 274
 275-- It should be noted, that it is generally a bad idea to follow the G_VALUE_NOCOPY_CONTENTS hint for reference counted types. Due to reentrancy requirements and reference count assertions performed by the GSignal code, reference counts should always be incremented for reference counted contents stored in the value->data array. To deviate from our string example for a moment, and taking a look at an exemplary implementation for collect_value() of GObject:
 276
 277-- {
 278--   if (collect_values[0].v_pointer)
 279--     {
 280--       GObject *object = G_OBJECT (collect_values[0].v_pointer);
 281
 282--       /* never honour G_VALUE_NOCOPY_CONTENTS for ref-counted types */
 283--       value->data[0].v_pointer = g_object_ref (object);
 284--       return NULL;
 285--     }
 286--   else
 287--     return g_strdup_printf ("Object passed as invalid NULL pointer");
 288-- }
 289
 290-- The reference count for valid objects is always incremented, regardless of collect_flags. For invalid objects, the example returns a newly allocated string without altering value. Upon success, collect_value() needs to return NULL, if however a malicious condition occurred, collect_value() may spew an error by returning a newly allocated non-NULL string, giving a suitable description of the error condition. The calling code makes no assumptions about the value contents being valid upon error returns, value is simply thrown away without further freeing. As such, it is a good idea to not allocate GValue contents, prior to returning an error, however, collect_values() is not obliged to return a correctly setup value for error returns, simply because any non-NULL return is considered a fatal condition so further program behaviour is undefined.
 291-- gchar *lcopy_format; 	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.
 292-- lcopy_value () 	This function is responsible for storing the value contents into arguments passed through a variable argument list which got collected into collect_values according to lcopy_format. n_collect_values equals the string length of lcopy_format, and collect_flags may contain G_VALUE_NOCOPY_CONTENTS. In contrast to collect_value(), lcopy_value() is obliged to always properly support G_VALUE_NOCOPY_CONTENTS. Similar to collect_value() the function may prematurely abort by returning a newly allocated string describing an error condition. To complete the string example:
 293
 294-- {
 295--   gchar **string_p = collect_values[0].v_pointer;
 296
 297--   if (!string_p)
 298--     return g_strdup_printf ("string location passed as NULL");
 299
 300--   if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
 301--     *string_p = value->data[0].v_pointer;
 302--   else
 303--     *string_p = g_strdup (value->data[0].v_pointer);
 304
 305-- }
 306
 307-- And an exemplary version of lcopy_value() for reference-counted types:
 308
 309-- {
 310--   GObject **object_p = collect_values[0].v_pointer;
 311
 312--   if (!object_p)
 313--     return g_strdup_printf ("object location passed as NULL");
 314--   if (!value->data[0].v_pointer)
 315--     *object_p = NULL;
 316--   else if (collect_flags & G_VALUE_NOCOPY_CONTENTS) /* always honour */
 317--     *object_p = value->data[0].v_pointer;
 318--   else
 319--     *object_p = g_object_ref (value->data[0].v_pointer);
 320--   return NULL;
 321-- }
 322
 323-- G_TYPE_FROM_INSTANCE()
 324
 325-- #define G_TYPE_FROM_INSTANCE(instance)                          (G_TYPE_FROM_CLASS (((GTypeInstance*) (instance))->g_class))
 326
 327-- Returns the type identifier from a given instance structure.
 328
 329-- This macro should only be used in type implementations.
 330-- instance : 	Location of a valid GTypeInstance structure.
 331-- G_TYPE_FROM_CLASS()
 332
 333-- #define G_TYPE_FROM_CLASS(g_class)                              (((GTypeClass*) (g_class))->g_type)
 334
 335-- Returns the type identifier from a given class structure.
 336
 337-- This macro should only be used in type implementations.
 338-- g_class : 	Location of a valid GTypeClass structure.
 339-- G_TYPE_FROM_INTERFACE()
 340
 341-- #define G_TYPE_FROM_INTERFACE(g_iface)                          (((GTypeInterface*) (g_iface))->g_type)
 342
 343-- Returns the type identifier from a given interface structure.
 344
 345-- This macro should only be used in type implementations.
 346-- g_iface : 	Location of a valid GTypeInterface structure.
 347-- G_TYPE_INSTANCE_GET_CLASS()
 348
 349-- #define G_TYPE_INSTANCE_GET_CLASS(instance, g_type, c_type)     (_G_TYPE_IGC ((instance), (g_type), c_type))
 350
 351-- Returns the class structure of a given instance, casted to a specified ancestor type g_type of the instance.
 352-- Warning
 353
 354-- Note that while calling a GInstanceInitFunc(), the class pointer gets modified, so it might not always return the expected pointer.
 355
 356-- This macro should only be used in type implementations.
 357-- instance : 	Location of the GTypeInstance structure.
 358-- g_type : 	The anchestor type of the class to be returned.
 359-- c_type : 	The corresponding C type of g_type.
 360-- G_TYPE_INSTANCE_GET_INTERFACE()
 361
 362-- #define G_TYPE_INSTANCE_GET_INTERFACE(instance, g_type, c_type) (_G_TYPE_IGI ((instance), (g_type), c_type))
 363
 364-- Returns the interface structure for interface g_type of a given instance.
 365
 366-- This macro should only be used in type implementations.
 367-- instance : 	Location of the GTypeInstance structure.
 368-- g_type : 	The interface type to be returned.
 369-- c_type : 	The corresponding C type of g_type.
 370-- G_TYPE_INSTANCE_GET_PRIVATE()
 371
 372-- #define G_TYPE_INSTANCE_GET_PRIVATE(instance, g_type, c_type)   ((c_type*) g_type_instance_get_private ((GTypeInstance*) (instance), (g_type)))
 373
 374-- 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().
 375
 376-- This macro should only be used in type implementations.
 377-- instance : 	the instance of a type deriving from private_type.
 378-- g_type : 	the type identifying which private data to retrieve.
 379-- c_type : 	The C type for the private structure.
 380
 381-- Since 2.4
 382-- G_TYPE_CHECK_INSTANCE()
 383
 384-- #define G_TYPE_CHECK_INSTANCE(instance)				(_G_TYPE_CHI ((GTypeInstance*) (instance)))
 385
 386-- Returns TRUE if instance is a valid GTypeInstance structure, otherwise emits a warning and returns FALSE.
 387
 388-- This macro should only be used in type implementations.
 389-- instance : 	Location of a GTypeInstance structure.
 390-- G_TYPE_CHECK_INSTANCE_CAST()
 391
 392-- #define G_TYPE_CHECK_INSTANCE_CAST(instance, g_type, c_type)    (_G_TYPE_CIC ((instance), (g_type), c_type))
 393
 394-- Checks that instance is an instance of the type identified by g_type and emits a warning if this is not the case. Returns instance casted to a pointer to c_type.
 395
 396-- This macro should only be used in type implementations.
 397-- instance : 	Location of a GTypeInstance structure.
 398-- g_type : 	The type to be returned.
 399-- c_type : 	The corresponding C type of g_type.
 400-- G_TYPE_CHECK_INSTANCE_TYPE()
 401
 402-- #define G_TYPE_CHECK_INSTANCE_TYPE(instance, g_type)            (_G_TYPE_CIT ((instance), (g_type)))
 403
 404-- Returns TRUE if instance is an instance of the type identified by g_type. Otherwise emits a warning and returns FALSE.
 405
 406-- This macro should only be used in type implementations.
 407-- instance : 	Location of a GTypeInstance structure.
 408-- g_type : 	The type to be checked
 409-- G_TYPE_CHECK_CLASS_CAST()
 410
 411-- #define G_TYPE_CHECK_CLASS_CAST(g_class, g_type, c_type)        (_G_TYPE_CCC ((g_class), (g_type), c_type))
 412
 413-- Checks that g_class is a class structure of the type identified by g_type and emits a warning if this is not the case. Returns g_class casted to a pointer to c_type.
 414
 415-- This macro should only be used in type implementations.
 416-- g_class : 	Location of a GTypeClass structure.
 417-- g_type : 	The type to be returned.
 418-- c_type : 	The corresponding C type of class structure of g_type.
 419-- G_TYPE_CHECK_CLASS_TYPE()
 420
 421-- #define G_TYPE_CHECK_CLASS_TYPE(g_class, g_type)                (_G_TYPE_CCT ((g_class), (g_type)))
 422
 423-- Returns TRUE if g_class is a class structure of the type identified by g_type. Otherwise emits a warning and returns FALSE.
 424
 425-- This macro should only be used in type implementations.
 426-- g_class : 	Location of a GTypeClass structure.
 427-- g_type : 	The type to be checked.
 428-- G_TYPE_CHECK_VALUE()
 429
 430-- #define G_TYPE_CHECK_VALUE(value)				(_G_TYPE_CHV ((value)))
 431
 432-- Returns TRUE if value has been initialized to hold values of a value type.
 433
 434-- This macro should only be used in type implementations.
 435-- value : 	a GValue
 436-- G_TYPE_CHECK_VALUE_TYPE()
 437
 438-- #define G_TYPE_CHECK_VALUE_TYPE(value, g_type)			(_G_TYPE_CVH ((value), (g_type)))
 439
 440-- Returns TRUE if value has been initialized to hold values of type g_type.
 441
 442-- This macro should only be used in type implementations.
 443-- value : 	a GValue
 444-- g_type : 	The type to be checked.
 445-- G_TYPE_FLAG_RESERVED_ID_BIT
 446
 447-- #define	G_TYPE_FLAG_RESERVED_ID_BIT	((GType) (1 << 0))
 448
 449-- A bit in the type number that's supposed to be left untouched.
 450-- g_type_init ()
 451
 452-- void        g_type_init                     (void);
 453
 454-- Prior to any use of the type system, g_type_init() has to be called to initialize the type system and assorted other code portions (such as the various fundamental type implementations or the signal system).
 455-- enum GTypeDebugFlags
 456
 457-- typedef enum	/*< skip >*/
 458-- {
 459--   G_TYPE_DEBUG_NONE	= 0,
 460--   G_TYPE_DEBUG_OBJECTS	= 1 << 0,
 461--   G_TYPE_DEBUG_SIGNALS	= 1 << 1,
 462--   G_TYPE_DEBUG_MASK	= 0x03
 463-- } GTypeDebugFlags;
 464
 465-- The GTypeDebugFlags enumeration values can be passed to g_type_init_with_debug_flags() to trigger debugging messages during runtime. Note that the messages can also be triggered by setting the GOBJECT_DEBUG environment variable to a ':'-separated list of "objects" and "signals".
 466-- G_TYPE_DEBUG_NONE 	Print no messages.
 467-- G_TYPE_DEBUG_OBJECTS 	Print messages about object bookkeeping.
 468-- G_TYPE_DEBUG_SIGNALS 	Print messages about signal emissions.
 469-- G_TYPE_DEBUG_MASK 	Mask covering all debug flags.
 470-- g_type_init_with_debug_flags ()
 471
 472-- void        g_type_init_with_debug_flags    (GTypeDebugFlags debug_flags);
 473
 474-- Similar to g_type_init(), but additionally sets debug flags.
 475-- debug_flags : 	Bitwise combination of GTypeDebugFlags values for debugging purposes.
 476-- g_type_name ()
 477
 478-- const gchar* g_type_name                    (GType type);
 479
 480-- Returns the unique name that is assigned to a type ID (this is the preferred method to find out whether a specific type has been registered for the passed in ID yet).
 481-- type : 	Type to return name for.
 482-- Returns : 	Static type name or NULL.
 483-- g_type_qname ()
 484
 485-- GQuark      g_type_qname                    (GType type);
 486
 487-- Return the corresponding quark of the type IDs name.
 488-- type : 	Type to return quark of type name for.
 489-- Returns : 	The type names quark or 0.
 490-- g_type_from_name ()
 491
 492-- GType       g_type_from_name                (const gchar *name);
 493
 494-- Lookup the type ID from a given type name, returns 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).
 495-- name : 	Type name to lookup.
 496-- Returns : 	Corresponding type ID or 0.
 497-- g_type_parent ()
 498
 499-- GType       g_type_parent                   (GType type);
 500
 501-- 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.
 502-- type : 	The derived type.
 503-- Returns : 	The parent type.
 504-- g_type_depth ()
 505
 506-- guint       g_type_depth                    (GType type);
 507
 508-- 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.
 509-- type : 	A GType value.
 510-- Returns : 	The depth of type.
 511-- g_type_next_base ()
 512
 513-- GType       g_type_next_base                (GType leaf_type,
 514--                                              GType root_type);
 515
 516-- Given a leaf_type and a root_type which is contained in its anchestry, 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.
 517-- leaf_type : 	Descendant of root_type and the type to be returned.
 518-- root_type : 	Immediate parent of the returned type.
 519-- Returns : 	Immediate child of root_type and anchestor of leaf_type.
 520											 
 521-- g_type_is_a ()
 522
 523-- gboolean    g_type_is_a                     (GType type,
 524--                                              GType is_a_type);
 525
 526-- 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.
 527-- type : 	Type to check anchestry for.
 528-- is_a_type : 	Possible anchestor of type or interface type could conform to.
 529-- Returns : 	TRUE if type is_a is_a_type holds true.
 530-- g_type_class_ref ()
 531
 532-- gpointer    g_type_class_ref                (GType type);
 533
 534-- Increments the reference count of the class structure belonging to type. This function will demand-create the class if it doesn't exist already.
 535-- type : 	Type ID of a classed type.
 536-- Returns : 	The GTypeClass structure for the given type ID.
 537-- g_type_class_peek ()
 538
 539-- gpointer    g_type_class_peek               (GType type);
 540
 541-- This function is essentially the same as g_type_class_ref(), except that the classes reference count isn't incremented. Therefore, this function may return NULL if the class of the type passed in does not currently exist (hasn't been referenced before).
 542-- type : 	Type ID of a classed type.
 543-- Returns : 	The GTypeClass structure for the given type ID or NULL if the class does not currently exist.
 544-- g_type_class_peek_static ()
 545
 546-- gpointer    g_type_class_peek_static        (GType type);
 547
 548-- A more efficient version of g_type_class_peek() which works only for static types.
 549-- type : 	Type ID of a classed type.
 550-- Returns : 	The GTypeClass structure for the given type ID or NULL if the class does not currently exist or is dynamically loaded.
 551
 552-- Since 2.4
 553-- g_type_class_unref ()
 554
 555-- void        g_type_class_unref              (gpointer g_class);
 556
 557-- 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.
 558-- g_class : 	The GTypeClass structure to unreference.
 559-- g_type_class_peek_parent ()
 560
 561-- gpointer    g_type_class_peek_parent        (gpointer g_class);
 562
 563-- This is a convenience function, often needed in class initializers. It essentially takes the immediate parent type of the class passed in, and returns the class structure thereof. 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:
 564
 565-- g_type_class_peek (g_type_parent (G_TYPE_FROM_CLASS (g_class)));
 566
 567-- g_class : 	The GTypeClass structure to retrieve the parent class for.
 568-- Returns : 	The parent class of g_class.
 569-- g_type_class_add_private ()
 570
 571-- void        g_type_class_add_private        (gpointer g_class,
 572--                                              gsize private_size);
 573
 574-- Registers a private structure for a instantiatable type; when an object is allocated, the private structures for the type and and all of its parent types are allocated sequentially in the same memory block as the public structures. 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.
 575
 576-- typedef struct _MyObjectPrivate MyObjectPrivate;
 577
 578-- struct _MyObjectPrivate {
 579--   int some_field;
 580-- };
 581
 582-- #define MY_OBJECT_GET_PRIVATE(o)  \
 583--    (G_TYPE_INSTANCE_GET_PRIVATE ((o), MY_TYPE_OBJECT, MyObjectPrivate))
 584
 585-- static void
 586-- my_object_class_init (MyObjectClass *klass)
 587-- {
 588--   g_type_class_add_private (klass, sizeof (MyObjectPrivate));
 589-- }
 590
 591-- static int
 592-- my_object_get_some_field (MyObject *my_object)
 593-- {
 594--   MyObjectPrivate *priv = MY_OBJECT_GET_PRIVATE (my_object);
 595
 596--   return priv->some_field;
 597-- }
 598
 599-- g_class : 	class structure for an instantiatable type
 600-- private_size : 	size of private structure.
 601
 602-- Since 2.4
 603-- g_type_interface_peek ()
 604
 605-- gpointer    g_type_interface_peek           (gpointer instance_class,
 606--                                              GType iface_type);
 607
 608-- Returns the GTypeInterface structure of an interface to which the passed in class conforms.
 609-- instance_class : 	A GTypeClass structure.
 610-- iface_type : 	An interface ID which this class conforms to.
 611-- Returns : 	The GTypeInterface structure of iface_type, or NULL if the class is not instantiated.
 612-- g_type_interface_peek_parent ()
 613
 614-- gpointer    g_type_interface_peek_parent    (gpointer g_iface);
 615
 616-- 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.
 617-- g_iface : 	A GTypeInterface structure.
 618-- Returns : 	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.
 619-- g_type_default_interface_ref ()
 620
 621-- gpointer    g_type_default_interface_ref    (GType g_type);
 622
 623-- Increments the reference count for the interface type g_type, and returns the default interface vtable for the type.
 624
 625-- If the type is not currently in use, then the default vtable for the type will be created and initalized 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.
 626-- g_type : 	an interface type
 627-- Returns : 	the default vtable for the interface; call g_type_default_interface_unref() when you are done using the interface.
 628
 629-- Since 2.4
 630-- g_type_default_interface_peek ()
 631
 632-- gpointer    g_type_default_interface_peek   (GType g_type);
 633
 634-- If the interface type g_type is currently in use, returns its default interface vtable.
 635-- g_type : 	an interface type
 636-- Returns : 	the default vtable for the interface; or NULL if the type is not currently in use.
 637
 638-- Since 2.4
 639-- g_type_default_interface_unref ()
 640
 641-- void        g_type_default_interface_unref  (gpointer g_iface);
 642
 643-- 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.
 644-- g_iface : 	the default vtable structure for a interface, as returned by g_type_default_interface_ref()
 645
 646-- Since 2.4
 647-- g_type_children ()
 648
 649-- GType*      g_type_children                 (GType type,
 650--                                              guint *n_children);
 651
 652-- Return a newly allocated and 0-terminated array of type IDs, listing the child types of type. The return value has to be g_free()ed after use.
 653-- type : 	The parent type.
 654-- n_children : 	Optional guint pointer to contain the number of child types.
 655-- Returns : 	Newly allocated and 0-terminated array of child types.
 656-- g_type_interfaces ()
 657
 658-- GType*      g_type_interfaces               (GType type,
 659--                                              guint *n_interfaces);
 660
 661-- Return a newly allocated and 0-terminated array of type IDs, listing the interface types that type conforms to. The return value has to be g_free()ed after use.
 662-- type : 	The type to list interface types for.
 663-- n_interfaces : 	Optional guint pointer to contain the number of interface types.
 664-- Returns : 	Newly allocated and 0-terminated array of interface types.
 665-- g_type_interface_prerequisites ()
 666
 667-- GType*      g_type_interface_prerequisites  (GType interface_type,
 668--                                              guint *n_prerequisites);
 669
 670-- Returns the prerequisites of an interfaces type.
 671-- interface_type : 	an interface type
 672-- n_prerequisites : 	location to return the number of prerequisites, or NULL
 673-- Returns : 	a newly-allocated zero-terminated array of GType containing the prerequisites of interface_type
 674
 675-- Since 2.2
 676-- g_type_set_qdata ()
 677
 678-- void        g_type_set_qdata                (GType type,
 679--                                              GQuark quark,
 680--                                              gpointer data);
 681
 682-- Attaches arbitrary data to a type.
 683-- type : 	a GType
 684-- quark : 	a GQuark id to identify the data
 685-- data : 	the data
 686-- g_type_get_qdata ()
 687
 688-- gpointer    g_type_get_qdata                (GType type,
 689--                                              GQuark quark);
 690
 691-- Obtains data which has previously been attached to type with g_type_set_qdata().
 692-- type : 	a GType
 693-- quark : 	a GQuark id to identify the data
 694-- Returns : 	the data, or NULL if no data was found
 695-- g_type_query ()
 696
 697-- void        g_type_query                    (GType type,
 698--                                              GTypeQuery *query);
 699
 700-- 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.
 701-- type : 	the GType value of a static, classed type.
 702-- query : 	A user provided structure that is filled in with constant values upon success.
 703-- GTypeQuery
 704
 705-- typedef struct {
 706--   GType		type;
 707--   const gchar  *type_name;
 708--   guint		class_size;
 709--   guint		instance_size;
 710-- } GTypeQuery;
 711
 712-- A structure holding information for a specific type. It is filled in by the g_type_query() function.
 713-- GType type; 	the GType value of the type.
 714-- const gchar *type_name; 	the name of the type.
 715-- guint class_size; 	the size of the class structure.
 716-- guint instance_size; 	the size of the instance structure.
 717-- GBaseInitFunc ()
 718
 719-- void        (*GBaseInitFunc)                (gpointer g_class);
 720
 721-- A callback function used by the type system to do base initialization of the class structures of derived types. It is called as part of the initialization process of all derived classes and should reallocate or reset all dynamic class members copied over from the parent class. Therefore class members, e.g. 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 intialization process.
 722-- g_class : 	The GTypeClass structure to initialize.
 723-- GBaseFinalizeFunc ()
 724
 725-- void        (*GBaseFinalizeFunc)            (gpointer g_class);
 726
 727-- 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 intialization is performed. See GClassInitFunc() for a discussion of the class intialization process.
 728-- g_class : 	The GTypeClass structure to finalize.
 729-- GClassInitFunc ()
 730
 731-- void        (*GClassInitFunc)               (gpointer g_class,
 732--                                              gpointer class_data);
 733
 734-- 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:
 735
 736-- 1 - Copying common members from the parent class over to the derived class structure.
 737
 738-- 2 - Zero initialization of the remaining members not copied over from the parent class.
 739
 740-- 3 - Invocation of the GBaseInitFunc() initializers of all parent types and the class' type.
 741
 742-- 4 - Invocation of the class' GClassInitFunc() initializer.
 743
 744-- 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:
 745
 746-- typedef struct {
 747--   GObjectClass parent_class;
 748--   gint         static_integer;
 749--   gchar       *dynamic_string;
 750-- } TypeAClass;
 751-- static void
 752-- type_a_base_class_init (TypeAClass *class)
 753-- {
 754--   class->dynamic_string = g_strdup ("some string");
 755-- }
 756-- static void
 757-- type_a_base_class_finalize (TypeAClass *class)
 758-- {
 759--   g_free (class->dynamic_string);
 760-- }
 761-- static void
 762-- type_a_class_init (TypeAClass *class)
 763-- {
 764--   class->static_integer = 42;
 765-- }
 766
 767-- typedef struct {
 768--   TypeAClass   parent_class;
 769--   gfloat       static_float;
 770--   GString     *dynamic_gstring;
 771-- } TypeBClass;
 772-- static void
 773-- type_b_base_class_init (TypeBClass *class)
 774-- {
 775--   class->dynamic_gstring = g_string_new ("some other string");
 776-- }
 777-- static void
 778-- type_b_base_class_finalize (TypeBClass *class)
 779-- {
 780--   g_string_free (class->dynamic_gstring);
 781-- }
 782-- static void
 783-- type_b_class_init (TypeBClass *class)
 784-- {
 785--   class->static_float = 3.14159265358979323846;
 786-- }
 787
 788-- 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() that allocates 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.
 789-- g_class : 	The GTypeClass structure to initialize.
 790-- class_data : 	The class_data member supplied via the GTypeInfo structure.
 791-- GClassFinalizeFunc ()
 792
 793-- void        (*GClassFinalizeFunc)           (gpointer g_class,
 794--                                              gpointer class_data);
 795
 796-- 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).
 797-- g_class : 	The GTypeClass structure to finalize.
 798-- class_data : 	The class_data member supplied via the GTypeInfo structure.
 799-- GInstanceInitFunc ()
 800
 801-- void        (*GInstanceInitFunc)            (GTypeInstance *instance,
 802--                                              gpointer g_class);
 803
 804-- 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, therefore 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.
 805-- instance : 	The instance to initialize.
 806-- g_class : 	The class of the type the instance is created for.
 807-- GInterfaceInitFunc ()
 808
 809-- void        (*GInterfaceInitFunc)           (gpointer g_iface,
 810--                                              gpointer iface_data);
 811
 812-- 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.
 813-- g_iface : 	The interface structure to initialize.
 814-- iface_data : 	The class_data supplied via the GTypeInfo structure.
 815-- GInterfaceFinalizeFunc ()
 816
 817-- void        (*GInterfaceFinalizeFunc)       (gpointer g_iface,
 818--                                              gpointer iface_data);
 819
 820-- 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.
 821-- g_iface : 	The interface structure to finalize.
 822-- iface_data : 	The class_data supplied via the GTypeInfo structure.
 823-- GTypeClassCacheFunc ()
 824
 825-- gboolean    (*GTypeClassCacheFunc)          (gpointer cache_data,
 826--                                              GTypeClass *g_class);
 827
 828-- 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.
 829
 830-- 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.
 831-- cache_data : 	data that was given to the g_type_add_class_cache_func() call
 832-- g_class : 	The GTypeClass structure which is unreferenced
 833-- Returns : 	TRUE to stop further GTypeClassCacheFuncs from being called, FALSE to continue.
 834-- enum GTypeFlags
 835
 836-- typedef enum    /*< skip >*/
 837-- {
 838--   G_TYPE_FLAG_ABSTRACT		= (1 << 4),
 839--   G_TYPE_FLAG_VALUE_ABSTRACT	= (1 << 5)
 840-- } GTypeFlags;
 841
 842-- Bit masks used to check or determine characteristics of a type.
 843-- G_TYPE_FLAG_ABSTRACT 	Indicates an abstract type. No instances can be created for an abstract type.
 844-- G_TYPE_FLAG_VALUE_ABSTRACT 	Indicates an abstract value type, i.e. a type that introduces a value table, but can't be used for g_value_init().
 845-- enum GTypeFundamentalFlags
 846
 847-- typedef enum    /*< skip >*/
 848-- {
 849--   G_TYPE_FLAG_CLASSED           = (1 << 0),
 850--   G_TYPE_FLAG_INSTANTIATABLE    = (1 << 1),
 851--   G_TYPE_FLAG_DERIVABLE         = (1 << 2),
 852--   G_TYPE_FLAG_DEEP_DERIVABLE    = (1 << 3)
 853-- } GTypeFundamentalFlags;
 854
 855-- Bit masks used to check or determine specific characteristics of a fundamental type.
 856-- G_TYPE_FLAG_CLASSED 	Indicates a classed type.
 857-- G_TYPE_FLAG_INSTANTIATABLE 	Indicates an instantiable type (implies classed).
 858-- G_TYPE_FLAG_DERIVABLE 	Indicates a flat derivable type.
 859-- G_TYPE_FLAG_DEEP_DERIVABLE 	Indicates a deep derivable type (implies derivable).
 860-- g_type_register_static ()
 861
 862-- GType       g_type_register_static          (GType parent_type,
 863--                                              const gchar *type_name,
 864--                                              const GTypeInfo *info,
 865--                                              GTypeFlags flags);
 866
 867-- 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.
 868-- parent_type : 	Type which this type will be derived from.
 869-- type_name : 	0-terminated string used as the name of the new type.
 870-- info : 	The GTypeInfo structure for this type.
 871-- flags : 	Bitwise combination of GTypeFlags values.
 872-- Returns : 	The new type identifier.
 873-- g_type_register_dynamic ()
 874
 875-- GType       g_type_register_dynamic         (GType parent_type,
 876--                                              const gchar *type_name,
 877--                                              GTypePlugin *plugin,
 878--                                              GTypeFlags flags);
 879
 880-- 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.
 881-- parent_type : 	Type which this type will be derived from.
 882-- type_name : 	0-terminated string used as the name of the new type.
 883-- plugin : 	The GTypePlugin structure to retrieve the GTypeInfo from.
 884-- flags : 	Bitwise combination of GTypeFlags values.
 885-- Returns : 	The new type identifier or G_TYPE_INVALID if registration failed.
 886-- g_type_register_fundamental ()
 887
 888-- GType       g_type_register_fundamental     (GType type_id,
 889--                                              const gchar *type_name,
 890--                                              const GTypeInfo *info,
 891--                                              const GTypeFundamentalInfo *finfo,
 892--                                              GTypeFlags flags);
 893
 894-- Registers type_id as the predefined identifier and type_name as the name of a fundamental type. 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.
 895-- type_id : 	A predefined GTypeFundamentals value.
 896-- type_name : 	0-terminated string used as the name of the new type.
 897-- info : 	The GTypeInfo structure for this type.
 898-- finfo : 	The GTypeFundamentalInfo structure for this type.
 899-- flags : 	Bitwise combination of GTypeFlags values.
 900-- Returns : 	The predefined type identifier.
 901-- g_type_add_interface_static ()
 902
 903-- void        g_type_add_interface_static     (GType instance_type,
 904--                                              GType interface_type,
 905--                                              const GInterfaceInfo *info);
 906
 907-- Adds the static interface_type to instantiable_type. The information contained in the GTypeInterfaceInfo structure pointed to by info is used to manage the relationship.
 908-- instance_type : 	GType value of an instantiable type.
 909-- interface_type : 	GType value of an interface type.
 910-- info : 	The GInterfaceInfo structure for this (instance_type, interface_type) combination.
 911-- g_type_add_interface_dynamic ()
 912
 913-- void        g_type_add_interface_dynamic    (GType instance_type,
 914--                                              GType interface_type,
 915--                                              GTypePlugin *plugin);
 916
 917-- Adds the dynamic interface_type to instantiable_type. The information contained in the GTypePlugin structure pointed to by plugin is used to manage the relationship.
 918-- instance_type : 	the GType value of an instantiable type.
 919-- interface_type : 	the GType value of an interface type.
 920-- plugin : 	the GTypePlugin structure to retrieve the GInterfaceInfo from.
 921-- g_type_interface_add_prerequisite ()
 922
 923-- void        g_type_interface_add_prerequisite
 924--                                             (GType interface_type,
 925--                                              GType prerequisite_type);
 926
 927-- 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.
 928-- interface_type : 	GType value of an interface type.
 929-- prerequisite_type : 	GType value of an interface or instantiatable type.
 930-- g_type_get_plugin ()
 931
 932-- GTypePlugin* g_type_get_plugin              (GType type);
 933
 934-- Returns the GTypePlugin structure for type or NULL if type does not have a GTypePlugin structure.
 935-- type : 	The GType to retrieve the plugin for.
 936-- Returns : 	The corresponding plugin if type is a dynamic type, NULL otherwise.
 937-- g_type_interface_get_plugin ()
 938
 939-- GTypePlugin* g_type_interface_get_plugin    (GType instance_type,
 940--                                              GType interface_type);
 941
 942-- 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().
 943-- instance_type : 	the GType value of an instantiatable type.
 944-- interface_type : 	the GType value of an interface type.
 945-- Returns : 	the GTypePlugin for the dynamic interface interface_type of instance_type.
 946-- g_type_fundamental_next ()
 947
 948-- GType       g_type_fundamental_next         (void);
 949
 950-- 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.
 951-- Returns : 	The nextmost fundamental type ID to be registered, or 0 if the type system ran out of fundamental type IDs.
 952-- g_type_fundamental ()
 953
 954-- GType       g_type_fundamental              (GType type_id);
 955
 956-- Internal function, used to extract the fundamental type ID portion. use G_TYPE_FUNDAMENTAL() instead.
 957-- type_id : 	valid type ID
 958-- Returns : 	fundamental type ID
 959-- g_type_create_instance ()
 960
 961-- GTypeInstance* g_type_create_instance       (GType type);
 962
 963-- 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 implementators 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. 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.
 964-- type : 	An instantiatable type to create an instance for.
 965-- Returns : 	An allocated and initialized instance, subject to further treatment by the fundamental type implementation.
 966-- g_type_free_instance ()
 967
 968-- void        g_type_free_instance            (GTypeInstance *instance);
 969
 970-- Frees an instance of a type, returning it to the instance pool for the type, if there is one.
 971
 972-- Like g_type_create_instance(), this function is reserved for implementors of fundamental types.
 973-- instance : 	an instance of a type.
 974-- g_type_add_class_cache_func ()
 975
 976-- void        g_type_add_class_cache_func     (gpointer cache_data,
 977--                                              GTypeClassCacheFunc cache_func);
 978
 979-- 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.
 980-- cache_data : 	data to be passed to cache_func
 981-- cache_func : 	a GTypeClassCacheFunc
 982-- g_type_remove_class_cache_func ()
 983
 984-- void        g_type_remove_class_cache_func  (gpointer cache_data,
 985--                                              GTypeClassCacheFunc cache_func);
 986
 987-- 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.
 988-- cache_data : 	data that was given when adding cache_func
 989-- cache_func : 	a GTypeClassCacheFunc
 990-- g_type_class_unref_uncached ()
 991
 992-- void        g_type_class_unref_uncached     (gpointer g_class);
 993
 994-- 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.
 995-- g_class : 	The GTypeClass structure to unreference.
 996-- g_type_add_interface_check ()
 997
 998-- void        g_type_add_interface_check      (gpointer check_data,
 999--                                              GTypeInterfaceCheckFunc check_func);
1000
1001-- Adds a function to be called after an interface vtable is initialized for any class. That is, after the interface_init member of GInterfaceInfo has been called.
1002
1003-- 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.
1004-- check_data : 	data to pass to check_func
1005-- check_func : 	function to be called after each interface is initialized.
1006
1007-- Since 2.4
1008-- g_type_remove_interface_check ()
1009
1010-- void        g_type_remove_interface_check   (gpointer check_data,
1011--                                              GTypeInterfaceCheckFunc check_func);
1012
1013-- Removes an interface check function added with g_type_add_interface_check().
1014-- check_data : 	callback data passed to g_type_add_interface_check()
1015-- check_func : 	callback function passed to g_type_add_interface_check()
1016
1017-- Since 2.4
1018-- GTypeInterfaceCheckFunc ()
1019
1020-- void        (*GTypeInterfaceCheckFunc)      (gpointer check_data,
1021--                                              gpointer g_iface);
1022
1023-- A callback called after an interface vtable is initialized. See g_type_add_interface_check().
1024-- check_data : 	data passed to g_type_add_interface_check().
1025-- g_iface : 	the interface that has been initialized
1026
1027-- Since 2.4
1028-- g_type_value_table_peek ()
1029
1030-- GTypeValueTable* g_type_value_table_peek    (GType type);
1031
1032-- Returns the location of the GTypeValueTable associated with type. Note, this function should only be used from source code that implements or has internal knowledge of the implementation of type.
1033-- type : 	A GType value.
1034-- Returns : 	Location of the GTypeValueTable associated with type or NULL if there is no GTypeValueTable associated with type.
1035-- G_DEFINE_TYPE()
1036
1037-- #define G_DEFINE_TYPE(TN, t_n, T_P)                         G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, 0, {})
1038
1039-- 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.
1040-- TN : 	The name of the new type, in Camel case.
1041-- t_n : 	The name of the new type, in lowercase, with words separated by '_'.
1042-- T_P : 	The GType of the parent type.
1043
1044-- Since 2.4
1045-- G_DEFINE_TYPE_WITH_CODE()
1046
1047-- #define G_DEFINE_TYPE_WITH_CODE(TN, t_n, T_P, _C_)          G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, 0, _C_)
1048
1049-- A convenience macro for type implementations. Similar to G_DEFINE_TYPE(), but allows 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.
1050-- TN : 	The name of the new type, in Camel case.
1051-- t_n : 	The name of the new type in lowercase, with words separated by '_'.
1052-- T_P : 	The GType of the parent type.
1053-- _C_ : 	Custom code that gets inserted in the *_get_type() function.
1054
1055-- Since 2.4
1056-- G_DEFINE_ABSTRACT_TYPE()
1057
1058-- #define G_DEFINE_ABSTRACT_TYPE(TN, t_n, T_P)                G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_ABSTRACT, {})
1059
1060-- A convenience macro for type implementations. Similar to G_DEFINE_TYPE(), but defines an abstract type. See G_DEFINE_TYPE_EXTENDED() for an example.
1061-- TN : 	The name of the new type, in Camel case.
1062-- t_n : 	The name of the new type, in lowercase, with words separated by '_'.
1063-- T_P : 	The GType of the parent type.
1064
1065-- Since 2.4
1066-- G_DEFINE_ABSTRACT_TYPE_WITH_CODE()
1067
1068-- #define G_DEFINE_ABSTRACT_TYPE_WITH_CODE(TN, t_n, T_P, _C_) G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_ABSTRACT, _C_)
1069
1070-- A convenience macro for type implementations. Similar to G_DEFINE_TYPE_WITH_CODE(), but defines an abstract type and allows 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.
1071-- TN : 	The name of the new type, in Camel case.
1072-- t_n : 	The name of the new type, in lowercase, with words separated by '_'.
1073-- T_P : 	The GType of the parent type.
1074-- _C_ : 	Custom code that gets inserted in the @type_name_get_type() function.
1075
1076-- Since 2.4
1077-- G_IMPLEMENT_INTERFACE()
1078
1079-- #define     G_IMPLEMENT_INTERFACE(TYPE_IFACE, iface_init)
1080
1081-- 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.
1082
1083-- Note that this macro can only be used together with the G_DEFINE_TYPE_* macros, since it depends on variable names from those macros.
1084-- TYPE_IFACE : 	The GType of the interface to add
1085-- iface_init : 	The interface init function
1086
1087-- Since 2.4
1088-- G_DEFINE_TYPE_EXTENDED()
1089
1090-- #define     G_DEFINE_TYPE_EXTENDED(TypeName, type_name, TYPE_PARENT, flags, CODE)
1091
1092-- The most general convenience macro for type implementations, on which G_DEFINE_TYPE(), etc are based.
1093
1094-- G_DEFINE_TYPE_EXTENDED (GtkGadget, 
1095--                         gtk_gadget, 
1096--                         GTK_TYPE_WIDGET,
1097--                         0, 
1098--                         G_IMPLEMENT_INTERFACE (TYPE_GIZMO, 
1099--                                                gtk_gadget_gizmo_init));
1100
1101-- expands to
1102
1103-- static void     gtk_gadget_init       (GtkGadget      *self);
1104-- static void     gtk_gadget_class_init (GtkGadgetClass *klass);
1105-- static gpointer gtk_gadget_parent_class = NULL;
1106-- static void     gtk_gadget_class_intern_init (gpointer klass)
1107-- {
1108--   gtk_gadget_parent_class = g_type_class_peek_parent (klass);
1109--   gtk_gadget_class_init ((GtkGadgetClass*) klass);
1110-- }
1111
1112-- GType
1113-- gtk_gadget_get_type (void)
1114-- {
1115--   static GType g_define_type_id = 0; 
1116--   if (G_UNLIKELY (g_define_type_id == 0)) 
1117--     { 
1118--       static const GTypeInfo g_define_type_info = { 
1119--         sizeof (GtkGadgetClass), 
1120--         (GBaseInitFunc) NULL, 
1121--         (GBaseFinalizeFunc) NULL, 
1122--         (GClassInitFunc) gtk_gadget_class_intern_init, 
1123--         (GClassFinalizeFunc) NULL, 
1124--         NULL,   /* class_data */ 
1125--         sizeof (GtkGadget), 
1126--         0,      /* n_preallocs */ 
1127--         (GInstanceInitFunc) gtk_gadget_init, 
1128--       }; 
1129--       g_define_type_id = g_type_register_static (GTK_TYPE_WIDGET, "GtkGadget", &g_define_type_info, 0); 
1130--       {
1131--         static const GInterfaceInfo g_implement_interface_info = {
1132--           (GInterfaceInitFunc) gtk_gadget_gizmo_init
1133--         };
1134--         g_type_add_interface_static (g_define_type_id, TYPE_GIZMO, &g_implement_interface_info);
1135--       } 
1136--     } 
1137--   return g_define_type_id; 
1138-- }
1139
1140-- 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.
1141-- TypeName : 	The name of the new type, in Camel case.
1142-- type_name : 	The name of the new type, in lowercase, with words separated by '_'.
1143-- TYPE_PARENT : 	The GType of the parent type.
1144-- flags : 	GTypeFlags to pass to g_type_register_static()
1145-- CODE : 	Custom code that gets inserted in the *_get_type() function.
1146
1147-- Since 2.4
1148-- G_TYPE_INVALID
1149
1150-- #define G_TYPE_INVALID			G_TYPE_MAKE_FUNDAMENTAL (0)
1151
1152-- An invalid GType, used as error return value in some functions which return a GType.
1153-- G_TYPE_NONE
1154
1155-- #define G_TYPE_NONE			G_TYPE_MAKE_FUNDAMENTAL (1)
1156
1157-- A fundamental type which is used as a replacement for the C void return type.
1158-- G_TYPE_INTERFACE
1159
1160-- #define G_TYPE_INTERFACE		G_TYPE_MAKE_FUNDAMENTAL (2)
1161
1162-- The fundamental type from which all interfaces are derived.
1163-- G_TYPE_CHAR
1164
1165-- #define G_TYPE_CHAR			G_TYPE_MAKE_FUNDAMENTAL (3)
1166
1167-- The fundamental type corresponding to gchar.
1168-- G_TYPE_UCHAR
1169
1170-- #define G_TYPE_UCHAR			G_TYPE_MAKE_FUNDAMENTAL (4)
1171
1172-- The fundamental type corresponding to guchar.
1173-- G_TYPE_BOOLEAN
1174
1175-- #define G_TYPE_BOOLEAN			G_TYPE_MAKE_FUNDAMENTAL (5)
1176
1177-- The fundamental type corresponding to gboolean.
1178-- G_TYPE_INT
1179
1180-- #define G_TYPE_INT			G_TYPE_MAKE_FUNDAMENTAL (6)
1181
1182-- The fundamental type corresponding to gint.
1183-- G_TYPE_UINT
1184
1185-- #define G_TYPE_UINT			G_TYPE_MAKE_FUNDAMENTAL (7)
1186
1187-- The fundamental type corresponding to guint.
1188-- G_TYPE_LONG
1189
1190-- #define G_TYPE_LONG			G_TYPE_MAKE_FUNDAMENTAL (8)
1191
1192-- The fundamental type corresponding to glong.
1193-- G_TYPE_ULONG
1194
1195-- #define G_TYPE_ULONG			G_TYPE_MAKE_FUNDAMENTAL (9)
1196
1197-- The fundamental type corresponding to gulong.
1198-- G_TYPE_INT64
1199
1200-- #define G_TYPE_INT64			G_TYPE_MAKE_FUNDAMENTAL (10)
1201
1202-- The fundamental type corresponding to gint64.
1203-- G_TYPE_UINT64
1204
1205-- #define G_TYPE_UINT64			G_TYPE_MAKE_FUNDAMENTAL (11)
1206
1207-- The fundamental type corresponding to guint64.
1208-- G_TYPE_ENUM
1209
1210-- #define G_TYPE_ENUM			G_TYPE_MAKE_FUNDAMENTAL (12)
1211
1212-- The fundamental type from which all enumeration types are derived.
1213-- G_TYPE_FLAGS
1214
1215-- #define G_TYPE_FLAGS			G_TYPE_MAKE_FUNDAMENTAL (13)
1216
1217-- The fundamental type from which all flags types are derived.
1218-- G_TYPE_FLOAT
1219
1220-- #define G_TYPE_FLOAT			G_TYPE_MAKE_FUNDAMENTAL (14)
1221
1222-- The fundamental type corresponding to gfloat.
1223-- G_TYPE_DOUBLE
1224
1225-- #define G_TYPE_DOUBLE			G_TYPE_MAKE_FUNDAMENTAL (15)
1226
1227-- The fundamental type corresponding to gdouble.
1228-- G_TYPE_STRING
1229
1230-- #define G_TYPE_STRING			G_TYPE_MAKE_FUNDAMENTAL (16)
1231
1232-- The fundamental type corresponding to nul-terminated C strings.
1233-- G_TYPE_POINTER
1234
1235-- #define G_TYPE_POINTER			G_TYPE_MAKE_FUNDAMENTAL (17)
1236
1237-- The fundamental ty