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      1 /* GObject - GLib Type, Object, Parameter and Signal Library
      2  * Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
      3  *
      4  * This library is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU Lesser General Public
      6  * License as published by the Free Software Foundation; either
      7  * version 2 of the License, or (at your option) any later version.
      8  *
      9  * This library is distributed in the hope that it will be useful,
     10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * Lesser General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU Lesser General
     15  * Public License along with this library; if not, write to the
     16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
     17  * Boston, MA 02111-1307, USA.
     18  */
     19 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
     20 #error "Only <glib-object.h> can be included directly."
     21 #endif
     22 
     23 #ifndef __G_TYPE_H__
     24 #define __G_TYPE_H__
     25 
     26 #include        <glib.h>
     27 
     28 G_BEGIN_DECLS
     29 
     30 /* Basic Type Macros
     31  */
     32 /**
     33  * G_TYPE_FUNDAMENTAL:
     34  * @type: A #GType value.
     35  *
     36  * The fundamental type which is the ancestor of @type.
     37  * Fundamental types are types that serve as ultimate bases for the derived types,
     38  * thus they are the roots of distinct inheritance hierarchies.
     39  */
     40 #define G_TYPE_FUNDAMENTAL(type)	(g_type_fundamental (type))
     41 /**
     42  * G_TYPE_FUNDAMENTAL_MAX:
     43  *
     44  * An integer constant that represents the number of identifiers reserved
     45  * for types that are assigned at compile-time.
     46  */
     47 #define	G_TYPE_FUNDAMENTAL_MAX		(255 << G_TYPE_FUNDAMENTAL_SHIFT)
     48 
     49 /* Constant fundamental types,
     50  * introduced by g_type_init().
     51  */
     52 /**
     53  * G_TYPE_INVALID:
     54  *
     55  * An invalid #GType used as error return value in some functions which return
     56  * a #GType.
     57  */
     58 #define G_TYPE_INVALID			G_TYPE_MAKE_FUNDAMENTAL (0)
     59 /**
     60  * G_TYPE_NONE:
     61  *
     62  * A fundamental type which is used as a replacement for the C
     63  * <literal>void</literal> return type.
     64  */
     65 #define G_TYPE_NONE			G_TYPE_MAKE_FUNDAMENTAL (1)
     66 /**
     67  * G_TYPE_INTERFACE:
     68  *
     69  * The fundamental type from which all interfaces are derived.
     70  */
     71 #define G_TYPE_INTERFACE		G_TYPE_MAKE_FUNDAMENTAL (2)
     72 /**
     73  * G_TYPE_CHAR:
     74  *
     75  * The fundamental type corresponding to #gchar.
     76  * The type designated by G_TYPE_CHAR is unconditionally an 8-bit signed integer.
     77  * This may or may not be the same type a the C type "gchar".
     78  */
     79 #define G_TYPE_CHAR			G_TYPE_MAKE_FUNDAMENTAL (3)
     80 /**
     81  * G_TYPE_UCHAR:
     82  *
     83  * The fundamental type corresponding to #guchar.
     84  */
     85 #define G_TYPE_UCHAR			G_TYPE_MAKE_FUNDAMENTAL (4)
     86 /**
     87  * G_TYPE_BOOLEAN:
     88  *
     89  * The fundamental type corresponding to #gboolean.
     90  */
     91 #define G_TYPE_BOOLEAN			G_TYPE_MAKE_FUNDAMENTAL (5)
     92 /**
     93  * G_TYPE_INT:
     94  *
     95  * The fundamental type corresponding to #gint.
     96  */
     97 #define G_TYPE_INT			G_TYPE_MAKE_FUNDAMENTAL (6)
     98 /**
     99  * G_TYPE_UINT:
    100  *
    101  * The fundamental type corresponding to #guint.
    102  */
    103 #define G_TYPE_UINT			G_TYPE_MAKE_FUNDAMENTAL (7)
    104 /**
    105  * G_TYPE_LONG:
    106  *
    107  * The fundamental type corresponding to #glong.
    108  */
    109 #define G_TYPE_LONG			G_TYPE_MAKE_FUNDAMENTAL (8)
    110 /**
    111  * G_TYPE_ULONG:
    112  *
    113  * The fundamental type corresponding to #gulong.
    114  */
    115 #define G_TYPE_ULONG			G_TYPE_MAKE_FUNDAMENTAL (9)
    116 /**
    117  * G_TYPE_INT64:
    118  *
    119  * The fundamental type corresponding to #gint64.
    120  */
    121 #define G_TYPE_INT64			G_TYPE_MAKE_FUNDAMENTAL (10)
    122 /**
    123  * G_TYPE_UINT64:
    124  *
    125  * The fundamental type corresponding to #guint64.
    126  */
    127 #define G_TYPE_UINT64			G_TYPE_MAKE_FUNDAMENTAL (11)
    128 /**
    129  * G_TYPE_ENUM:
    130  *
    131  * The fundamental type from which all enumeration types are derived.
    132  */
    133 #define G_TYPE_ENUM			G_TYPE_MAKE_FUNDAMENTAL (12)
    134 /**
    135  * G_TYPE_FLAGS:
    136  *
    137  * The fundamental type from which all flags types are derived.
    138  */
    139 #define G_TYPE_FLAGS			G_TYPE_MAKE_FUNDAMENTAL (13)
    140 /**
    141  * G_TYPE_FLOAT:
    142  *
    143  * The fundamental type corresponding to #gfloat.
    144  */
    145 #define G_TYPE_FLOAT			G_TYPE_MAKE_FUNDAMENTAL (14)
    146 /**
    147  * G_TYPE_DOUBLE:
    148  *
    149  * The fundamental type corresponding to #gdouble.
    150  */
    151 #define G_TYPE_DOUBLE			G_TYPE_MAKE_FUNDAMENTAL (15)
    152 /**
    153  * G_TYPE_STRING:
    154  *
    155  * The fundamental type corresponding to nul-terminated C strings.
    156  */
    157 #define G_TYPE_STRING			G_TYPE_MAKE_FUNDAMENTAL (16)
    158 /**
    159  * G_TYPE_POINTER:
    160  *
    161  * The fundamental type corresponding to #gpointer.
    162  */
    163 #define G_TYPE_POINTER			G_TYPE_MAKE_FUNDAMENTAL (17)
    164 /**
    165  * G_TYPE_BOXED:
    166  *
    167  * The fundamental type from which all boxed types are derived.
    168  */
    169 #define G_TYPE_BOXED			G_TYPE_MAKE_FUNDAMENTAL (18)
    170 /**
    171  * G_TYPE_PARAM:
    172  *
    173  * The fundamental type from which all #GParamSpec types are derived.
    174  */
    175 #define G_TYPE_PARAM			G_TYPE_MAKE_FUNDAMENTAL (19)
    176 /**
    177  * G_TYPE_OBJECT:
    178  *
    179  * The fundamental type for #GObject.
    180  */
    181 #define G_TYPE_OBJECT			G_TYPE_MAKE_FUNDAMENTAL (20)
    182 
    183 
    184 /* Reserved fundamental type numbers to create new fundamental
    185  * type IDs with G_TYPE_MAKE_FUNDAMENTAL().
    186  * Send email to gtk-devel-list (at) gnome.org for reservations.
    187  */
    188 /**
    189  * G_TYPE_FUNDAMENTAL_SHIFT:
    190  *
    191  * Shift value used in converting numbers to type IDs.
    192  */
    193 #define	G_TYPE_FUNDAMENTAL_SHIFT	(2)
    194 /**
    195  * G_TYPE_MAKE_FUNDAMENTAL:
    196  * @x: the fundamental type number.
    197  *
    198  * Get the type ID for the fundamental type number @x.
    199  * Use g_type_fundamental_next() instead of this macro to create new fundamental
    200  * types.
    201  *
    202  * Returns: the GType
    203  */
    204 #define	G_TYPE_MAKE_FUNDAMENTAL(x)	((GType) ((x) << G_TYPE_FUNDAMENTAL_SHIFT))
    205 /**
    206  * G_TYPE_RESERVED_GLIB_FIRST:
    207  *
    208  * First fundamental type number to create a new fundamental type id with
    209  * G_TYPE_MAKE_FUNDAMENTAL() reserved for GLib.
    210  */
    211 #define G_TYPE_RESERVED_GLIB_FIRST	(21)
    212 /**
    213  * G_TYPE_RESERVED_GLIB_LAST:
    214  *
    215  * Last fundamental type number reserved for GLib.
    216  */
    217 #define G_TYPE_RESERVED_GLIB_LAST	(31)
    218 /**
    219  * G_TYPE_RESERVED_BSE_FIRST:
    220  *
    221  * First fundamental type number to create a new fundamental type id with
    222  * G_TYPE_MAKE_FUNDAMENTAL() reserved for BSE.
    223  */
    224 #define G_TYPE_RESERVED_BSE_FIRST	(32)
    225 /**
    226  * G_TYPE_RESERVED_BSE_LAST:
    227  *
    228  * Last fundamental type number reserved for BSE.
    229  */
    230 #define G_TYPE_RESERVED_BSE_LAST	(48)
    231 /**
    232  * G_TYPE_RESERVED_USER_FIRST:
    233  *
    234  * First available fundamental type number to create new fundamental
    235  * type id with G_TYPE_MAKE_FUNDAMENTAL().
    236  */
    237 #define G_TYPE_RESERVED_USER_FIRST	(49)
    238 
    239 
    240 /* Type Checking Macros
    241  */
    242 /**
    243  * G_TYPE_IS_FUNDAMENTAL:
    244  * @type: A #GType value.
    245  *
    246  * Checks if @type is a fundamental type.
    247  *
    248  * Returns: %TRUE on success.
    249  */
    250 #define G_TYPE_IS_FUNDAMENTAL(type)             ((type) <= G_TYPE_FUNDAMENTAL_MAX)
    251 /**
    252  * G_TYPE_IS_DERIVED:
    253  * @type: A #GType value.
    254  *
    255  * Checks if @type is derived (or in object-oriented terminology:
    256  * inherited) from another type (this holds true for all non-fundamental
    257  * types).
    258  *
    259  * Returns: %TRUE on success.
    260  */
    261 #define G_TYPE_IS_DERIVED(type)                 ((type) > G_TYPE_FUNDAMENTAL_MAX)
    262 /**
    263  * G_TYPE_IS_INTERFACE:
    264  * @type: A #GType value.
    265  *
    266  * Checks if @type is an interface type.
    267  * An interface type provides a pure API, the implementation
    268  * of which is provided by another type (which is then said to conform
    269  * to the interface).  GLib interfaces are somewhat analogous to Java
    270  * interfaces and C++ classes containing only pure virtual functions,
    271  * with the difference that GType interfaces are not derivable (but see
    272  * g_type_interface_add_prerequisite() for an alternative).
    273  *
    274  * Returns: %TRUE on success.
    275  */
    276 #define G_TYPE_IS_INTERFACE(type)               (G_TYPE_FUNDAMENTAL (type) == G_TYPE_INTERFACE)
    277 /**
    278  * G_TYPE_IS_CLASSED:
    279  * @type: A #GType value.
    280  *
    281  * Checks if @type is a classed type.
    282  *
    283  * Returns: %TRUE on success.
    284  */
    285 #define G_TYPE_IS_CLASSED(type)                 (g_type_test_flags ((type), G_TYPE_FLAG_CLASSED))
    286 /**
    287  * G_TYPE_IS_INSTANTIATABLE:
    288  * @type: A #GType value.
    289  *
    290  * Checks if @type can be instantiated.  Instantiation is the
    291  * process of creating an instance (object) of this type.
    292  *
    293  * Returns: %TRUE on success.
    294  */
    295 #define G_TYPE_IS_INSTANTIATABLE(type)          (g_type_test_flags ((type), G_TYPE_FLAG_INSTANTIATABLE))
    296 /**
    297  * G_TYPE_IS_DERIVABLE:
    298  * @type: A #GType value.
    299  *
    300  * Checks if @type is a derivable type.  A derivable type can
    301  * be used as the base class of a flat (single-level) class hierarchy.
    302  *
    303  * Returns: %TRUE on success.
    304  */
    305 #define G_TYPE_IS_DERIVABLE(type)               (g_type_test_flags ((type), G_TYPE_FLAG_DERIVABLE))
    306 /**
    307  * G_TYPE_IS_DEEP_DERIVABLE:
    308  * @type: A #GType value.
    309  *
    310  * Checks if @type is a deep derivable type.  A deep derivable type
    311  * can be used as the base class of a deep (multi-level) class hierarchy.
    312  *
    313  * Returns: %TRUE on success.
    314  */
    315 #define G_TYPE_IS_DEEP_DERIVABLE(type)          (g_type_test_flags ((type), G_TYPE_FLAG_DEEP_DERIVABLE))
    316 /**
    317  * G_TYPE_IS_ABSTRACT:
    318  * @type: A #GType value.
    319  *
    320  * Checks if @type is an abstract type.  An abstract type can not be
    321  * instantiated and is normally used as an abstract base class for
    322  * derived classes.
    323  *
    324  * Returns: %TRUE on success.
    325  */
    326 #define G_TYPE_IS_ABSTRACT(type)                (g_type_test_flags ((type), G_TYPE_FLAG_ABSTRACT))
    327 /**
    328  * G_TYPE_IS_VALUE_ABSTRACT:
    329  * @type: A #GType value.
    330  *
    331  * Checks if @type is an abstract value type.  An abstract value type introduces
    332  * a value table, but can't be used for g_value_init() and is normally used as
    333  * an abstract base type for derived value types.
    334  *
    335  * Returns: %TRUE on success.
    336  */
    337 #define G_TYPE_IS_VALUE_ABSTRACT(type)          (g_type_test_flags ((type), G_TYPE_FLAG_VALUE_ABSTRACT))
    338 /**
    339  * G_TYPE_IS_VALUE_TYPE:
    340  * @type: A #GType value.
    341  *
    342  * Checks if @type is a value type and can be used with g_value_init().
    343  *
    344  * Returns: %TRUE on success.
    345  */
    346 #define G_TYPE_IS_VALUE_TYPE(type)              (g_type_check_is_value_type (type))
    347 /**
    348  * G_TYPE_HAS_VALUE_TABLE:
    349  * @type: A #GType value.
    350  *
    351  * Checks if @type has a #GTypeValueTable.
    352  *
    353  * Returns: %TRUE on success.
    354  */
    355 #define G_TYPE_HAS_VALUE_TABLE(type)            (g_type_value_table_peek (type) != NULL)
    356 
    357 
    358 /* Typedefs
    359  */
    360 /**
    361  * GType:
    362  *
    363  * A numerical value which represents the unique identifier of a registered
    364  * type.
    365  */
    366 #if     GLIB_SIZEOF_SIZE_T != GLIB_SIZEOF_LONG || !defined __cplusplus
    367 typedef gsize                           GType;
    368 #else   /* for historic reasons, C++ links against gulong GTypes */
    369 typedef gulong                          GType;
    370 #endif
    371 typedef struct _GValue                  GValue;
    372 typedef union  _GTypeCValue             GTypeCValue;
    373 typedef struct _GTypePlugin             GTypePlugin;
    374 typedef struct _GTypeClass              GTypeClass;
    375 typedef struct _GTypeInterface          GTypeInterface;
    376 typedef struct _GTypeInstance           GTypeInstance;
    377 typedef struct _GTypeInfo               GTypeInfo;
    378 typedef struct _GTypeFundamentalInfo    GTypeFundamentalInfo;
    379 typedef struct _GInterfaceInfo          GInterfaceInfo;
    380 typedef struct _GTypeValueTable         GTypeValueTable;
    381 typedef struct _GTypeQuery		GTypeQuery;
    382 
    383 
    384 /* Basic Type Structures
    385  */
    386 /**
    387  * GTypeClass:
    388  *
    389  * An opaque structure used as the base of all classes.
    390  */
    391 struct _GTypeClass
    392 {
    393   /*< private >*/
    394   GType g_type;
    395 };
    396 /**
    397  * GTypeInstance:
    398  *
    399  * An opaque structure used as the base of all type instances.
    400  */
    401 struct _GTypeInstance
    402 {
    403   /*< private >*/
    404   GTypeClass *g_class;
    405 };
    406 /**
    407  * GTypeInterface:
    408  *
    409  * An opaque structure used as the base of all interface types.
    410  */
    411 struct _GTypeInterface
    412 {
    413   /*< private >*/
    414   GType g_type;         /* iface type */
    415   GType g_instance_type;
    416 };
    417 /**
    418  * GTypeQuery:
    419  * @type: the #GType value of the type.
    420  * @type_name: the name of the type.
    421  * @class_size: the size of the class structure.
    422  * @instance_size: the size of the instance structure.
    423  *
    424  * A structure holding information for a specific type. It is
    425  * filled in by the g_type_query() function.
    426  */
    427 struct _GTypeQuery
    428 {
    429   GType		type;
    430   const gchar  *type_name;
    431   guint		class_size;
    432   guint		instance_size;
    433 };
    434 
    435 
    436 /* Casts, checks and accessors for structured types
    437  * usage of these macros is reserved to type implementations only
    438  */
    439 /*< protected >*/
    440 /**
    441  * G_TYPE_CHECK_INSTANCE:
    442  * @instance: Location of a #GTypeInstance structure.
    443  *
    444  * Checks if @instance is a valid #GTypeInstance structure,
    445  * otherwise issues a warning and returns %FALSE.
    446  *
    447  * This macro should only be used in type implementations.
    448  *
    449  * Returns: %TRUE on success.
    450  */
    451 #define G_TYPE_CHECK_INSTANCE(instance)				(_G_TYPE_CHI ((GTypeInstance*) (instance)))
    452 /**
    453  * G_TYPE_CHECK_INSTANCE_CAST:
    454  * @instance: Location of a #GTypeInstance structure.
    455  * @g_type: The type to be returned.
    456  * @c_type: The corresponding C type of @g_type.
    457  *
    458  * Checks that @instance is an instance of the type identified by @g_type
    459  * and issues a warning if this is not the case. Returns @instance casted
    460  * to a pointer to @c_type.
    461  *
    462  * This macro should only be used in type implementations.
    463  */
    464 #define G_TYPE_CHECK_INSTANCE_CAST(instance, g_type, c_type)    (_G_TYPE_CIC ((instance), (g_type), c_type))
    465 /**
    466  * G_TYPE_CHECK_INSTANCE_TYPE:
    467  * @instance: Location of a #GTypeInstance structure.
    468  * @g_type: The type to be checked
    469  *
    470  * Checks if @instance is an instance of the type identified by @g_type.
    471  *
    472  * This macro should only be used in type implementations.
    473  *
    474  * Returns: %TRUE on success.
    475  */
    476 #define G_TYPE_CHECK_INSTANCE_TYPE(instance, g_type)            (_G_TYPE_CIT ((instance), (g_type)))
    477 /**
    478  * G_TYPE_INSTANCE_GET_CLASS:
    479  * @instance: Location of the #GTypeInstance structure.
    480  * @g_type: The #GType of the class to be returned.
    481  * @c_type: The C type of the class structure.
    482  *
    483  * Get the class structure of a given @instance, casted
    484  * to a specified ancestor type @g_type of the instance.
    485  *
    486  * Note that while calling a GInstanceInitFunc(), the class pointer gets
    487  * modified, so it might not always return the expected pointer.
    488  *
    489  * This macro should only be used in type implementations.
    490  *
    491  * Returns: a pointer to the class structure
    492  */
    493 #define G_TYPE_INSTANCE_GET_CLASS(instance, g_type, c_type)     (_G_TYPE_IGC ((instance), (g_type), c_type))
    494 /**
    495  * G_TYPE_INSTANCE_GET_INTERFACE:
    496  * @instance: Location of the #GTypeInstance structure.
    497  * @g_type: The #GType of the interface to be returned.
    498  * @c_type: The C type of the interface structure.
    499  *
    500  * Get the interface structure for interface @g_type of a given @instance.
    501  *
    502  * This macro should only be used in type implementations.
    503  *
    504  * Returns: a pointer to the interface structure
    505  */
    506 #define G_TYPE_INSTANCE_GET_INTERFACE(instance, g_type, c_type) (_G_TYPE_IGI ((instance), (g_type), c_type))
    507 /**
    508  * G_TYPE_CHECK_CLASS_CAST:
    509  * @g_class: Location of a #GTypeClass structure.
    510  * @g_type: The type to be returned.
    511  * @c_type: The corresponding C type of class structure of @g_type.
    512  *
    513  * Checks that @g_class is a class structure of the type identified by @g_type
    514  * and issues a warning if this is not the case. Returns @g_class casted
    515  * to a pointer to @c_type.
    516  *
    517  * This macro should only be used in type implementations.
    518  */
    519 #define G_TYPE_CHECK_CLASS_CAST(g_class, g_type, c_type)        (_G_TYPE_CCC ((g_class), (g_type), c_type))
    520 /**
    521  * G_TYPE_CHECK_CLASS_TYPE:
    522  * @g_class: Location of a #GTypeClass structure.
    523  * @g_type: The type to be checked.
    524  *
    525  * Checks if @g_class is a class structure of the type identified by
    526  * @g_type.
    527  *
    528  * This macro should only be used in type implementations.
    529  *
    530  * Returns: %TRUE on success.
    531  */
    532 #define G_TYPE_CHECK_CLASS_TYPE(g_class, g_type)                (_G_TYPE_CCT ((g_class), (g_type)))
    533 /**
    534  * G_TYPE_CHECK_VALUE:
    535  * @value: a #GValue
    536  *
    537  * Checks if @value has been initialized to hold values
    538  * of a value type.
    539  *
    540  * This macro should only be used in type implementations.
    541  *
    542  * Returns: %TRUE on success.
    543  */
    544 #define G_TYPE_CHECK_VALUE(value)				(_G_TYPE_CHV ((value)))
    545 /**
    546  * G_TYPE_CHECK_VALUE_TYPE:
    547  * @value: a #GValue
    548  * @g_type: The type to be checked.
    549  *
    550  * Checks if @value has been initialized to hold values
    551  * of type @g_type.
    552  *
    553  * This macro should only be used in type implementations.
    554  *
    555  * Returns: %TRUE on success.
    556  */
    557 #define G_TYPE_CHECK_VALUE_TYPE(value, g_type)			(_G_TYPE_CVH ((value), (g_type)))
    558 /**
    559  * G_TYPE_FROM_INSTANCE:
    560  * @instance: Location of a valid #GTypeInstance structure.
    561  *
    562  * Get the type identifier from a given @instance structure.
    563  *
    564  * This macro should only be used in type implementations.
    565  *
    566  * Returns: the #GType
    567  */
    568 #define G_TYPE_FROM_INSTANCE(instance)                          (G_TYPE_FROM_CLASS (((GTypeInstance*) (instance))->g_class))
    569 /**
    570  * G_TYPE_FROM_CLASS:
    571  * @g_class: Location of a valid #GTypeClass structure.
    572  *
    573  * Get the type identifier from a given @class structure.
    574  *
    575  * This macro should only be used in type implementations.
    576  *
    577  * Returns: the #GType
    578  */
    579 #define G_TYPE_FROM_CLASS(g_class)                              (((GTypeClass*) (g_class))->g_type)
    580 /**
    581  * G_TYPE_FROM_INTERFACE:
    582  * @g_iface: Location of a valid #GTypeInterface structure.
    583  *
    584  * Get the type identifier from a given @interface structure.
    585  *
    586  * This macro should only be used in type implementations.
    587  *
    588  * Returns: the #GType
    589  */
    590 #define G_TYPE_FROM_INTERFACE(g_iface)                          (((GTypeInterface*) (g_iface))->g_type)
    591 
    592 /**
    593  * G_TYPE_INSTANCE_GET_PRIVATE:
    594  * @instance: the instance of a type deriving from @private_type.
    595  * @g_type: the type identifying which private data to retrieve.
    596  * @c_type: The C type for the private structure.
    597  *
    598  * Gets the private structure for a particular type.
    599  * The private structure must have been registered in the
    600  * class_init function with g_type_class_add_private().
    601  *
    602  * This macro should only be used in type implementations.
    603  *
    604  * Since: 2.4
    605  * Returns: a pointer to the private data structure.
    606  */
    607 #define G_TYPE_INSTANCE_GET_PRIVATE(instance, g_type, c_type)   ((c_type*) g_type_instance_get_private ((GTypeInstance*) (instance), (g_type)))
    608 
    609 
    610 /**
    611  * GTypeDebugFlags:
    612  * @G_TYPE_DEBUG_NONE: Print no messages.
    613  * @G_TYPE_DEBUG_OBJECTS: Print messages about object bookkeeping.
    614  * @G_TYPE_DEBUG_SIGNALS: Print messages about signal emissions.
    615  * @G_TYPE_DEBUG_MASK: Mask covering all debug flags.
    616  *
    617  * The <type>GTypeDebugFlags</type> enumeration values can be passed to
    618  * g_type_init_with_debug_flags() to trigger debugging messages during runtime.
    619  * Note that the messages can also be triggered by setting the
    620  * <envar>GOBJECT_DEBUG</envar> environment variable to a ':'-separated list of
    621  * "objects" and "signals".
    622  */
    623 typedef enum	/*< skip >*/
    624 {
    625   G_TYPE_DEBUG_NONE	= 0,
    626   G_TYPE_DEBUG_OBJECTS	= 1 << 0,
    627   G_TYPE_DEBUG_SIGNALS	= 1 << 1,
    628   G_TYPE_DEBUG_MASK	= 0x03
    629 } GTypeDebugFlags;
    630 
    631 
    632 /* --- prototypes --- */
    633 void                  g_type_init                    (void);
    634 void                  g_type_init_with_debug_flags   (GTypeDebugFlags  debug_flags);
    635 G_CONST_RETURN gchar* g_type_name                    (GType            type);
    636 GQuark                g_type_qname                   (GType            type);
    637 GType                 g_type_from_name               (const gchar     *name);
    638 GType                 g_type_parent                  (GType            type);
    639 guint                 g_type_depth                   (GType            type);
    640 GType                 g_type_next_base               (GType            leaf_type,
    641 						      GType            root_type);
    642 gboolean              g_type_is_a                    (GType            type,
    643 						      GType            is_a_type);
    644 gpointer              g_type_class_ref               (GType            type);
    645 gpointer              g_type_class_peek              (GType            type);
    646 gpointer              g_type_class_peek_static       (GType            type);
    647 void                  g_type_class_unref             (gpointer         g_class);
    648 gpointer              g_type_class_peek_parent       (gpointer         g_class);
    649 gpointer              g_type_interface_peek          (gpointer         instance_class,
    650 						      GType            iface_type);
    651 gpointer              g_type_interface_peek_parent   (gpointer         g_iface);
    652 
    653 gpointer              g_type_default_interface_ref   (GType            g_type);
    654 gpointer              g_type_default_interface_peek  (GType            g_type);
    655 void                  g_type_default_interface_unref (gpointer         g_iface);
    656 
    657 /* g_free() the returned arrays */
    658 GType*                g_type_children                (GType            type,
    659 						      guint           *n_children);
    660 GType*                g_type_interfaces              (GType            type,
    661 						      guint           *n_interfaces);
    662 
    663 /* per-type _static_ data */
    664 void                  g_type_set_qdata               (GType            type,
    665 						      GQuark           quark,
    666 						      gpointer         data);
    667 gpointer              g_type_get_qdata               (GType            type,
    668 						      GQuark           quark);
    669 void		      g_type_query		     (GType	       type,
    670 						      GTypeQuery      *query);
    671 
    672 
    673 /* --- type registration --- */
    674 /**
    675  * GBaseInitFunc:
    676  * @g_class: The #GTypeClass structure to initialize.
    677  *
    678  * A callback function used by the type system to do base initialization
    679  * of the class structures of derived types. It is called as part of the
    680  * initialization process of all derived classes and should reallocate
    681  * or reset all dynamic class members copied over from the parent class.
    682  * For example, class members (such as strings) that are not sufficiently
    683  * handled by a plain memory copy of the parent class into the derived class
    684  * have to be altered. See GClassInitFunc() for a discussion of the class
    685  * intialization process.
    686  */
    687 typedef void   (*GBaseInitFunc)              (gpointer         g_class);
    688 /**
    689  * GBaseFinalizeFunc:
    690  * @g_class: The #GTypeClass structure to finalize.
    691  *
    692  * A callback function used by the type system to finalize those portions
    693  * of a derived types class structure that were setup from the corresponding
    694  * GBaseInitFunc() function. Class finalization basically works the inverse
    695  * way in which class intialization is performed.
    696  * See GClassInitFunc() for a discussion of the class intialization process.
    697  */
    698 typedef void   (*GBaseFinalizeFunc)          (gpointer         g_class);
    699 /**
    700  * GClassInitFunc:
    701  * @g_class: The #GTypeClass structure to initialize.
    702  * @class_data: The @class_data member supplied via the #GTypeInfo structure.
    703  *
    704  * A callback function used by the type system to initialize the class
    705  * of a specific type. This function should initialize all static class
    706  * members.
    707  * The initialization process of a class involves:
    708  * <itemizedlist>
    709  * <listitem><para>
    710  * 	1 - Copying common members from the parent class over to the
    711  * 	derived class structure.
    712  * </para></listitem>
    713  * <listitem><para>
    714  * 	2 -  Zero initialization of the remaining members not copied
    715  * 	over from the parent class.
    716  * </para></listitem>
    717  * <listitem><para>
    718  * 	3 - Invocation of the GBaseInitFunc() initializers of all parent
    719  * 	types and the class' type.
    720  * </para></listitem>
    721  * <listitem><para>
    722  * 	4 - Invocation of the class' GClassInitFunc() initializer.
    723  * </para></listitem>
    724  * </itemizedlist>
    725  * Since derived classes are partially initialized through a memory copy
    726  * of the parent class, the general rule is that GBaseInitFunc() and
    727  * GBaseFinalizeFunc() should take care of necessary reinitialization
    728  * and release of those class members that were introduced by the type
    729  * that specified these GBaseInitFunc()/GBaseFinalizeFunc().
    730  * GClassInitFunc() should only care about initializing static
    731  * class members, while dynamic class members (such as allocated strings
    732  * or reference counted resources) are better handled by a GBaseInitFunc()
    733  * for this type, so proper initialization of the dynamic class members
    734  * is performed for class initialization of derived types as well.
    735  * An example may help to correspond the intend of the different class
    736  * initializers:
    737  *
    738  * |[
    739  * typedef struct {
    740  *   GObjectClass parent_class;
    741  *   gint         static_integer;
    742  *   gchar       *dynamic_string;
    743  * } TypeAClass;
    744  * static void
    745  * type_a_base_class_init (TypeAClass *class)
    746  * {
    747  *   class->dynamic_string = g_strdup ("some string");
    748  * }
    749  * static void
    750  * type_a_base_class_finalize (TypeAClass *class)
    751  * {
    752  *   g_free (class->dynamic_string);
    753  * }
    754  * static void
    755  * type_a_class_init (TypeAClass *class)
    756  * {
    757  *   class->static_integer = 42;
    758  * }
    759  *
    760  * typedef struct {
    761  *   TypeAClass   parent_class;
    762  *   gfloat       static_float;
    763  *   GString     *dynamic_gstring;
    764  * } TypeBClass;
    765  * static void
    766  * type_b_base_class_init (TypeBClass *class)
    767  * {
    768  *   class->dynamic_gstring = g_string_new ("some other string");
    769  * }
    770  * static void
    771  * type_b_base_class_finalize (TypeBClass *class)
    772  * {
    773  *   g_string_free (class->dynamic_gstring);
    774  * }
    775  * static void
    776  * type_b_class_init (TypeBClass *class)
    777  * {
    778  *   class->static_float = 3.14159265358979323846;
    779  * }
    780  * ]|
    781  * Initialization of TypeBClass will first cause initialization of
    782  * TypeAClass (derived classes reference their parent classes, see
    783  * g_type_class_ref() on this).
    784  * Initialization of TypeAClass roughly involves zero-initializing its fields,
    785  * then calling its GBaseInitFunc() type_a_base_class_init() to allocate
    786  * its dynamic members (dynamic_string), and finally calling its GClassInitFunc()
    787  * type_a_class_init() to initialize its static members (static_integer).
    788  * The first step in the initialization process of TypeBClass is then
    789  * a plain memory copy of the contents of TypeAClass into TypeBClass and
    790  * zero-initialization of the remaining fields in TypeBClass.
    791  * The dynamic members of TypeAClass within TypeBClass now need
    792  * reinitialization which is performed by calling type_a_base_class_init()
    793  * with an argument of TypeBClass.
    794  * After that, the GBaseInitFunc() of TypeBClass, type_b_base_class_init()
    795  * is called to allocate the dynamic members of TypeBClass (dynamic_gstring),
    796  * and finally the GClassInitFunc() of TypeBClass, type_b_class_init(),
    797  * is called to complete the initialization process with the static members
    798  * (static_float).
    799  * Corresponding finalization counter parts to the GBaseInitFunc() functions
    800  * have to be provided to release allocated resources at class finalization
    801  * time.
    802  */
    803 typedef void   (*GClassInitFunc)             (gpointer         g_class,
    804 					      gpointer         class_data);
    805 /**
    806  * GClassFinalizeFunc:
    807  * @g_class: The #GTypeClass structure to finalize.
    808  * @class_data: The @class_data member supplied via the #GTypeInfo structure.
    809  *
    810  * A callback function used by the type system to finalize a class.
    811  * This function is rarely needed, as dynamically allocated class resources
    812  * should be handled by GBaseInitFunc() and GBaseFinalizeFunc().
    813  * Also, specification of a GClassFinalizeFunc() in the #GTypeInfo
    814  * structure of a static type is invalid, because classes of static types
    815  * will never be finalized (they are artificially kept alive when their
    816  * reference count drops to zero).
    817  */
    818 typedef void   (*GClassFinalizeFunc)         (gpointer         g_class,
    819 					      gpointer         class_data);
    820 /**
    821  * GInstanceInitFunc:
    822  * @instance: The instance to initialize.
    823  * @g_class: The class of the type the instance is created for.
    824  *
    825  * A callback function used by the type system to initialize a new
    826  * instance of a type. This function initializes all instance members and
    827  * allocates any resources required by it.
    828  * Initialization of a derived instance involves calling all its parent
    829  * types instance initializers, so the class member of the instance
    830  * is altered during its initialization to always point to the class that
    831  * belongs to the type the current initializer was introduced for.
    832  */
    833 typedef void   (*GInstanceInitFunc)          (GTypeInstance   *instance,
    834 					      gpointer         g_class);
    835 /**
    836  * GInterfaceInitFunc:
    837  * @g_iface: The interface structure to initialize.
    838  * @iface_data: The @interface_data supplied via the #GInterfaceInfo structure.
    839  *
    840  * A callback function used by the type system to initialize a new
    841  * interface.  This function should initialize all internal data and
    842  * allocate any resources required by the interface.
    843  */
    844 typedef void   (*GInterfaceInitFunc)         (gpointer         g_iface,
    845 					      gpointer         iface_data);
    846 /**
    847  * GInterfaceFinalizeFunc:
    848  * @g_iface: The interface structure to finalize.
    849  * @iface_data: The @interface_data supplied via the #GInterfaceInfo structure.
    850  *
    851  * A callback function used by the type system to finalize an interface.
    852  * This function should destroy any internal data and release any resources
    853  * allocated by the corresponding GInterfaceInitFunc() function.
    854  */
    855 typedef void   (*GInterfaceFinalizeFunc)     (gpointer         g_iface,
    856 					      gpointer         iface_data);
    857 /**
    858  * GTypeClassCacheFunc:
    859  * @cache_data: data that was given to the g_type_add_class_cache_func() call
    860  * @g_class: The #GTypeClass structure which is unreferenced
    861  *
    862  * A callback function which is called when the reference count of a class
    863  * drops to zero. It may use g_type_class_ref() to prevent the class from
    864  * being freed. You should not call g_type_class_unref() from a
    865  * #GTypeClassCacheFunc function to prevent infinite recursion, use
    866  * g_type_class_unref_uncached() instead.
    867  *
    868  * The functions have to check the class id passed in to figure
    869  * whether they actually want to cache the class of this type, since all
    870  * classes are routed through the same #GTypeClassCacheFunc chain.
    871  *
    872  * Returns: %TRUE to stop further #GTypeClassCacheFunc<!-- -->s from being
    873  *  called, %FALSE to continue.
    874  */
    875 typedef gboolean (*GTypeClassCacheFunc)	     (gpointer	       cache_data,
    876 					      GTypeClass      *g_class);
    877 /**
    878  * GTypeInterfaceCheckFunc:
    879  * @check_data: data passed to g_type_add_interface_check().
    880  * @g_iface: the interface that has been initialized
    881  *
    882  * A callback called after an interface vtable is initialized.
    883  * See g_type_add_interface_check().
    884  *
    885  * Since: 2.4
    886  */
    887 typedef void     (*GTypeInterfaceCheckFunc)  (gpointer	       check_data,
    888 					      gpointer         g_iface);
    889 /**
    890  * GTypeFundamentalFlags:
    891  * @G_TYPE_FLAG_CLASSED: Indicates a classed type.
    892  * @G_TYPE_FLAG_INSTANTIATABLE: Indicates an instantiable type (implies classed).
    893  * @G_TYPE_FLAG_DERIVABLE: Indicates a flat derivable type.
    894  * @G_TYPE_FLAG_DEEP_DERIVABLE: Indicates a deep derivable type (implies derivable).
    895  *
    896  * Bit masks used to check or determine specific characteristics of a
    897  * fundamental type.
    898  */
    899 typedef enum    /*< skip >*/
    900 {
    901   G_TYPE_FLAG_CLASSED           = (1 << 0),
    902   G_TYPE_FLAG_INSTANTIATABLE    = (1 << 1),
    903   G_TYPE_FLAG_DERIVABLE         = (1 << 2),
    904   G_TYPE_FLAG_DEEP_DERIVABLE    = (1 << 3)
    905 } GTypeFundamentalFlags;
    906 /**
    907  * GTypeFlags:
    908  * @G_TYPE_FLAG_ABSTRACT: Indicates an abstract type. No instances can be
    909  *  created for an abstract type.
    910  * @G_TYPE_FLAG_VALUE_ABSTRACT: Indicates an abstract value type, i.e. a type
    911  *  that introduces a value table, but can't be used for
    912  *  g_value_init().
    913  *
    914  * Bit masks used to check or determine characteristics of a type.
    915  */
    916 typedef enum    /*< skip >*/
    917 {
    918   G_TYPE_FLAG_ABSTRACT		= (1 << 4),
    919   G_TYPE_FLAG_VALUE_ABSTRACT	= (1 << 5)
    920 } GTypeFlags;
    921 /**
    922  * GTypeInfo:
    923  * @class_size: Size of the class structure (required for interface, classed and instantiatable types).
    924  * @base_init: Location of the base initialization function (optional).
    925  * @base_finalize: Location of the base finalization function (optional).
    926  * @class_init: Location of the class initialization function for
    927  *  classed and instantiatable types. Location of the default vtable
    928  *  inititalization function for interface types. (optional) This function
    929  *  is used both to fill in virtual functions in the class or default vtable,
    930  *  and to do type-specific setup such as registering signals and object
    931  *  properties.
    932  * @class_finalize: Location of the class finalization function for
    933  *  classed and instantiatable types. Location fo the default vtable
    934  *  finalization function for interface types. (optional)
    935  * @class_data: User-supplied data passed to the class init/finalize functions.
    936  * @instance_size: Size of the instance (object) structure (required for instantiatable types only).
    937  * @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 <link linkend="glib-Memory-Slices">slice allocator</link> now.
    938  * @instance_init: Location of the instance initialization function (optional, for instantiatable types only).
    939  * @value_table: A #GTypeValueTable function table for generic handling of GValues of this type (usually only
    940  *  useful for fundamental types).
    941  *
    942  * This structure is used to provide the type system with the information
    943  * required to initialize and destruct (finalize) a type's class and
    944  * its instances.
    945  * The initialized structure is passed to the g_type_register_static() function
    946  * (or is copied into the provided #GTypeInfo structure in the
    947  * g_type_plugin_complete_type_info()). The type system will perform a deep
    948  * copy of this structure, so its memory does not need to be persistent
    949  * across invocation of g_type_register_static().
    950  */
    951 struct _GTypeInfo
    952 {
    953   /* interface types, classed types, instantiated types */
    954   guint16                class_size;
    955 
    956   GBaseInitFunc          base_init;
    957   GBaseFinalizeFunc      base_finalize;
    958 
    959   /* interface types, classed types, instantiated types */
    960   GClassInitFunc         class_init;
    961   GClassFinalizeFunc     class_finalize;
    962   gconstpointer          class_data;
    963 
    964   /* instantiated types */
    965   guint16                instance_size;
    966   guint16                n_preallocs;
    967   GInstanceInitFunc      instance_init;
    968 
    969   /* value handling */
    970   const GTypeValueTable	*value_table;
    971 };
    972 /**
    973  * GTypeFundamentalInfo:
    974  * @type_flags: #GTypeFundamentalFlags describing the characteristics of the fundamental type
    975  *
    976  * A structure that provides information to the type system which is
    977  * used specifically for managing fundamental types.
    978  */
    979 struct _GTypeFundamentalInfo
    980 {
    981   GTypeFundamentalFlags  type_flags;
    982 };
    983 /**
    984  * GInterfaceInfo:
    985  * @interface_init: location of the interface initialization function
    986  * @interface_finalize: location of the interface finalization function
    987  * @interface_data: user-supplied data passed to the interface init/finalize functions
    988  *
    989  * A structure that provides information to the type system which is
    990  * used specifically for managing interface types.
    991  */
    992 struct _GInterfaceInfo
    993 {
    994   GInterfaceInitFunc     interface_init;
    995   GInterfaceFinalizeFunc interface_finalize;
    996   gpointer               interface_data;
    997 };
    998 /**
    999  * GTypeValueTable:
   1000  * @value_init: Default initialize @values contents by poking values
   1001  *  directly into the value->data array. The data array of
   1002  *  the #GValue passed into this function was zero-filled
   1003  *  with <function>memset()</function>, so no care has to
   1004  *  be taken to free any
   1005  *  old contents. E.g. for the implementation of a string
   1006  *  value that may never be %NULL, the implementation might
   1007  *  look like:
   1008  *  |[
   1009  *  value->data[0].v_pointer = g_strdup ("");
   1010  *  ]|
   1011  * @value_free: Free any old contents that might be left in the
   1012  *  data array of the passed in @value. No resources may
   1013  *  remain allocated through the #GValue contents after
   1014  *  this function returns. E.g. for our above string type:
   1015  *  |[
   1016  *  // only free strings without a specific flag for static storage
   1017  *  if (!(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
   1018  *    g_free (value->data[0].v_pointer);
   1019  *  ]|
   1020  * @value_copy: @dest_value is a #GValue with zero-filled data section
   1021  *  and @src_value is a properly setup #GValue of same or
   1022  *  derived type.
   1023  *  The purpose of this function is to copy the contents of
   1024  *  @src_value into @dest_value in a way, that even after
   1025  *  @src_value has been freed, the contents of @dest_value
   1026  *  remain valid. String type example:
   1027  *  |[
   1028  *  dest_value->data[0].v_pointer = g_strdup (src_value->data[0].v_pointer);
   1029  *  ]|
   1030  * @value_peek_pointer: If the value contents fit into a pointer, such as objects
   1031  *  or strings, return this pointer, so the caller can peek at
   1032  *  the current contents. To extend on our above string example:
   1033  *  |[
   1034  *  return value->data[0].v_pointer;
   1035  *  ]|
   1036  * @collect_format: A string format describing how to collect the contents of
   1037  *  this value bit-by-bit. Each character in the format represents
   1038  *  an argument to be collected, and the characters themselves indicate
   1039  *  the type of the argument. Currently supported arguments are:
   1040  *  <variablelist>
   1041  *  <varlistentry><term /><listitem><para>
   1042  *  'i' - Integers. passed as collect_values[].v_int.
   1043  *  </para></listitem></varlistentry>
   1044  *  <varlistentry><term /><listitem><para>
   1045  *  'l' - Longs. passed as collect_values[].v_long.
   1046  *  </para></listitem></varlistentry>
   1047  *  <varlistentry><term /><listitem><para>
   1048  *  'd' - Doubles. passed as collect_values[].v_double.
   1049  *  </para></listitem></varlistentry>
   1050  *  <varlistentry><term /><listitem><para>
   1051  *  'p' - Pointers. passed as collect_values[].v_pointer.
   1052  *  </para></listitem></varlistentry>
   1053  *  </variablelist>
   1054  *  It should be noted that for variable argument list construction,
   1055  *  ANSI C promotes every type smaller than an integer to an int, and
   1056  *  floats to doubles. So for collection of short int or char, 'i'
   1057  *  needs to be used, and for collection of floats 'd'.
   1058  * @collect_value: The collect_value() function is responsible for converting the
   1059  *  values collected from a variable argument list into contents
   1060  *  suitable for storage in a GValue. This function should setup
   1061  *  @value similar to value_init(); e.g. for a string value that
   1062  *  does not allow %NULL pointers, it needs to either spew an error,
   1063  *  or do an implicit conversion by storing an empty string.
   1064  *  The @value passed in to this function has a zero-filled data
   1065  *  array, so just like for value_init() it is guaranteed to not
   1066  *  contain any old contents that might need freeing.
   1067  *  @n_collect_values is exactly the string length of @collect_format,
   1068  *  and @collect_values is an array of unions #GTypeCValue with
   1069  *  length @n_collect_values, containing the collected values
   1070  *  according to @collect_format.
   1071  *  @collect_flags is an argument provided as a hint by the caller.
   1072  *  It may contain the flag %G_VALUE_NOCOPY_CONTENTS indicating,
   1073  *  that the collected value contents may be considered "static"
   1074  *  for the duration of the @value lifetime.
   1075  *  Thus an extra copy of the contents stored in @collect_values is
   1076  *  not required for assignment to @value.
   1077  *  For our above string example, we continue with:
   1078  *  |[
   1079  *  if (!collect_values[0].v_pointer)
   1080  *    value->data[0].v_pointer = g_strdup ("");
   1081  *  else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
   1082  *  {
   1083  *    value->data[0].v_pointer = collect_values[0].v_pointer;
   1084  *    // keep a flag for the value_free() implementation to not free this string
   1085  *    value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
   1086  *  }
   1087  *  else
   1088  *    value->data[0].v_pointer = g_strdup (collect_values[0].v_pointer);
   1089  *  return NULL;
   1090  *  ]|
   1091  *  It should be noted, that it is generally a bad idea to follow the
   1092  *  #G_VALUE_NOCOPY_CONTENTS hint for reference counted types. Due to
   1093  *  reentrancy requirements and reference count assertions performed
   1094  *  by the #GSignal code, reference counts should always be incremented
   1095  *  for reference counted contents stored in the value->data array.
   1096  *  To deviate from our string example for a moment, and taking a look
   1097  *  at an exemplary implementation for collect_value() of #GObject:
   1098  *  |[
   1099  *  if (collect_values[0].v_pointer)
   1100  *  {
   1101  *    GObject *object = G_OBJECT (collect_values[0].v_pointer);
   1102  *    // never honour G_VALUE_NOCOPY_CONTENTS for ref-counted types
   1103  *    value->data[0].v_pointer = g_object_ref (object);
   1104  *    return NULL;
   1105  *  }
   1106  *  else
   1107  *    return g_strdup_printf ("Object passed as invalid NULL pointer");
   1108  *  }
   1109  *  ]|
   1110  *  The reference count for valid objects is always incremented,
   1111  *  regardless of @collect_flags. For invalid objects, the example
   1112  *  returns a newly allocated string without altering @value.
   1113  *  Upon success, collect_value() needs to return %NULL. If, however,
   1114  *  an error condition occurred, collect_value() may spew an
   1115  *  error by returning a newly allocated non-%NULL string, giving
   1116  *  a suitable description of the error condition.
   1117  *  The calling code makes no assumptions about the @value
   1118  *  contents being valid upon error returns, @value
   1119  *  is simply thrown away without further freeing. As such, it is
   1120  *  a good idea to not allocate #GValue contents, prior to returning
   1121  *  an error, however, collect_values() is not obliged to return
   1122  *  a correctly setup @value for error returns, simply because
   1123  *  any non-%NULL return is considered a fatal condition so further
   1124  *  program behaviour is undefined.
   1125  * @lcopy_format: Format description of the arguments to collect for @lcopy_value,
   1126  *  analogous to @collect_format. Usually, @lcopy_format string consists
   1127  *  only of 'p's to provide lcopy_value() with pointers to storage locations.
   1128  * @lcopy_value: This function is responsible for storing the @value contents into
   1129  *  arguments passed through a variable argument list which got
   1130  *  collected into @collect_values according to @lcopy_format.
   1131  *  @n_collect_values equals the string length of @lcopy_format,
   1132  *  and @collect_flags may contain %G_VALUE_NOCOPY_CONTENTS.
   1133  *  In contrast to collect_value(), lcopy_value() is obliged to
   1134  *  always properly support %G_VALUE_NOCOPY_CONTENTS.
   1135  *  Similar to collect_value() the function may prematurely abort
   1136  *  by returning a newly allocated string describing an error condition.
   1137  *  To complete the string example:
   1138  *  |[
   1139  *  gchar **string_p = collect_values[0].v_pointer;
   1140  *  if (!string_p)
   1141  *    return g_strdup_printf ("string location passed as NULL");
   1142  *  if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
   1143  *    *string_p = value->data[0].v_pointer;
   1144  *  else
   1145  *    *string_p = g_strdup (value->data[0].v_pointer);
   1146  *  ]|
   1147  *  And an illustrative version of lcopy_value() for
   1148  *  reference-counted types:
   1149  *  |[
   1150  *  GObject **object_p = collect_values[0].v_pointer;
   1151  *  if (!object_p)
   1152  *    return g_strdup_printf ("object location passed as NULL");
   1153  *  if (!value->data[0].v_pointer)
   1154  *    *object_p = NULL;
   1155  *  else if (collect_flags & G_VALUE_NOCOPY_CONTENTS) // always honour
   1156  *    *object_p = value->data[0].v_pointer;
   1157  *  else
   1158  *    *object_p = g_object_ref (value->data[0].v_pointer);
   1159  *  return NULL;
   1160  *  ]|
   1161  *
   1162  * The #GTypeValueTable provides the functions required by the #GValue implementation,
   1163  * to serve as a container for values of a type.
   1164  */
   1165 
   1166 struct _GTypeValueTable
   1167 {
   1168   void     (*value_init)         (GValue       *value);
   1169   void     (*value_free)         (GValue       *value);
   1170   void     (*value_copy)         (const GValue *src_value,
   1171 				  GValue       *dest_value);
   1172   /* varargs functionality (optional) */
   1173   gpointer (*value_peek_pointer) (const GValue *value);
   1174   gchar	    *collect_format;
   1175   gchar*   (*collect_value)      (GValue       *value,
   1176 				  guint         n_collect_values,
   1177 				  GTypeCValue  *collect_values,
   1178 				  guint		collect_flags);
   1179   gchar	    *lcopy_format;
   1180   gchar*   (*lcopy_value)        (const GValue *value,
   1181 				  guint         n_collect_values,
   1182 				  GTypeCValue  *collect_values,
   1183 				  guint		collect_flags);
   1184 };
   1185 GType g_type_register_static		(GType			     parent_type,
   1186 					 const gchar		    *type_name,
   1187 					 const GTypeInfo	    *info,
   1188 					 GTypeFlags		     flags);
   1189 GType g_type_register_static_simple     (GType                       parent_type,
   1190 					 const gchar                *type_name,
   1191 					 guint                       class_size,
   1192 					 GClassInitFunc              class_init,
   1193 					 guint                       instance_size,
   1194 					 GInstanceInitFunc           instance_init,
   1195 					 GTypeFlags	             flags);
   1196 
   1197 GType g_type_register_dynamic		(GType			     parent_type,
   1198 					 const gchar		    *type_name,
   1199 					 GTypePlugin		    *plugin,
   1200 					 GTypeFlags		     flags);
   1201 GType g_type_register_fundamental	(GType			     type_id,
   1202 					 const gchar		    *type_name,
   1203 					 const GTypeInfo	    *info,
   1204 					 const GTypeFundamentalInfo *finfo,
   1205 					 GTypeFlags		     flags);
   1206 void  g_type_add_interface_static	(GType			     instance_type,
   1207 					 GType			     interface_type,
   1208 					 const GInterfaceInfo	    *info);
   1209 void  g_type_add_interface_dynamic	(GType			     instance_type,
   1210 					 GType			     interface_type,
   1211 					 GTypePlugin		    *plugin);
   1212 void  g_type_interface_add_prerequisite (GType			     interface_type,
   1213 					 GType			     prerequisite_type);
   1214 GType*g_type_interface_prerequisites    (GType                       interface_type,
   1215 					 guint                      *n_prerequisites);
   1216 void     g_type_class_add_private       (gpointer                    g_class,
   1217                                          gsize                       private_size);
   1218 gpointer g_type_instance_get_private    (GTypeInstance              *instance,
   1219                                          GType                       private_type);
   1220 
   1221 
   1222 /* --- GType boilerplate --- */
   1223 /**
   1224  * G_DEFINE_TYPE:
   1225  * @TN: The name of the new type, in Camel case.
   1226  * @t_n: The name of the new type, in lowercase, with words
   1227  *  separated by '_'.
   1228  * @T_P: The #GType of the parent type.
   1229  *
   1230  * A convenience macro for type implementations, which declares a
   1231  * class initialization function, an instance initialization function (see #GTypeInfo for information about
   1232  * these) and a static variable named @t_n<!-- -->_parent_class pointing to the parent class. Furthermore, it defines
   1233  * a *_get_type() function. See G_DEFINE_TYPE_EXTENDED() for an example.
   1234  *
   1235  * Since: 2.4
   1236  */
   1237 #define G_DEFINE_TYPE(TN, t_n, T_P)			    G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, 0, {})
   1238 /**
   1239  * G_DEFINE_TYPE_WITH_CODE:
   1240  * @TN: The name of the new type, in Camel case.
   1241  * @t_n: The name of the new type in lowercase, with words separated by '_'.
   1242  * @T_P: The #GType of the parent type.
   1243  * @_C_: Custom code that gets inserted in the *_get_type() function.
   1244  *
   1245  * A convenience macro for type implementations.
   1246  * Similar to G_DEFINE_TYPE(), but allows to insert custom code into the
   1247  * *_get_type() function, e.g. interface implementations via G_IMPLEMENT_INTERFACE().
   1248  * See G_DEFINE_TYPE_EXTENDED() for an example.
   1249  *
   1250  * Since: 2.4
   1251  */
   1252 #define G_DEFINE_TYPE_WITH_CODE(TN, t_n, T_P, _C_)	    _G_DEFINE_TYPE_EXTENDED_BEGIN (TN, t_n, T_P, 0) {_C_;} _G_DEFINE_TYPE_EXTENDED_END()
   1253 /**
   1254  * G_DEFINE_ABSTRACT_TYPE:
   1255  * @TN: The name of the new type, in Camel case.
   1256  * @t_n: The name of the new type, in lowercase, with words
   1257  *  separated by '_'.
   1258  * @T_P: The #GType of the parent type.
   1259  *
   1260  * A convenience macro for type implementations.
   1261  * Similar to G_DEFINE_TYPE(), but defines an abstract type.
   1262  * See G_DEFINE_TYPE_EXTENDED() for an example.
   1263  *
   1264  * Since: 2.4
   1265  */
   1266 #define G_DEFINE_ABSTRACT_TYPE(TN, t_n, T_P)		    G_DEFINE_TYPE_EXTENDED (TN, t_n, T_P, G_TYPE_FLAG_ABSTRACT, {})
   1267 /**
   1268  * G_DEFINE_ABSTRACT_TYPE_WITH_CODE:
   1269  * @TN: The name of the new type, in Camel case.
   1270  * @t_n: The name of the new type, in lowercase, with words
   1271  *  separated by '_'.
   1272  * @T_P: The #GType of the parent type.
   1273  * @_C_: Custom code that gets inserted in the @type_name_get_type() function.
   1274  *
   1275  * A convenience macro for type implementations.
   1276  * Similar to G_DEFINE_TYPE_WITH_CODE(), but defines an abstract type and allows to
   1277  * insert custom code into the *_get_type() function, e.g. interface implementations
   1278  * via G_IMPLEMENT_INTERFACE(). See G_DEFINE_TYPE_EXTENDED() for an example.
   1279  *
   1280  * Since: 2.4
   1281  */
   1282 #define G_DEFINE_ABSTRACT_TYPE_WITH_CODE(TN, t_n, T_P, _C_) _G_DEFINE_TYPE_EXTENDED_BEGIN (TN, t_n, T_P, G_TYPE_FLAG_ABSTRACT) {_C_;} _G_DEFINE_TYPE_EXTENDED_END()
   1283 /**
   1284  * G_DEFINE_TYPE_EXTENDED:
   1285  * @TN: The name of the new type, in Camel case.
   1286  * @t_n: The name of the new type, in lowercase, with words
   1287  *    separated by '_'.
   1288  * @T_P: The #GType of the parent type.
   1289  * @_f_: #GTypeFlags to pass to g_type_register_static()
   1290  * @_C_: Custom code that gets inserted in the *_get_type() function.
   1291  *
   1292  * The most general convenience macro for type implementations, on which
   1293  * G_DEFINE_TYPE(), etc are based.
   1294  *
   1295  * |[
   1296  * G_DEFINE_TYPE_EXTENDED (GtkGadget,
   1297  *                         gtk_gadget,
   1298  *                         GTK_TYPE_WIDGET,
   1299  *                         0,
   1300  *                         G_IMPLEMENT_INTERFACE (TYPE_GIZMO,
   1301  *                                                gtk_gadget_gizmo_init));
   1302  * ]|
   1303  * expands to
   1304  * |[
   1305  * static void     gtk_gadget_init       (GtkGadget      *self);
   1306  * static void     gtk_gadget_class_init (GtkGadgetClass *klass);
   1307  * static gpointer gtk_gadget_parent_class = NULL;
   1308  * static void     gtk_gadget_class_intern_init (gpointer klass)
   1309  * {
   1310  *   gtk_gadget_parent_class = g_type_class_peek_parent (klass);
   1311  *   gtk_gadget_class_init ((GtkGadgetClass*) klass);
   1312  * }
   1313  *
   1314  * GType
   1315  * gtk_gadget_get_type (void)
   1316  * {
   1317  *   static volatile gsize g_define_type_id__volatile = 0;
   1318  *   if (g_once_init_enter (&g_define_type_id__volatile))
   1319  *     {
   1320  *       GType g_define_type_id =
   1321  *         g_type_register_static_simple (GTK_TYPE_WIDGET,
   1322  *                                        g_intern_static_string ("GtkGadget"),
   1323  *                                        sizeof (GtkGadgetClass),
   1324  *                                        (GClassInitFunc) gtk_gadget_class_intern_init,
   1325  *                                        sizeof (GtkGadget),
   1326  *                                        (GInstanceInitFunc) gtk_gadget_init,
   1327  *                                        (GTypeFlags) flags);
   1328  *       {
   1329  *         static const GInterfaceInfo g_implement_interface_info = {
   1330  *           (GInterfaceInitFunc) gtk_gadget_gizmo_init
   1331  *         };
   1332  *         g_type_add_interface_static (g_define_type_id, TYPE_GIZMO, &g_implement_interface_info);
   1333  *       }
   1334  *       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
   1335  *     }
   1336  *   return g_define_type_id__volatile;
   1337  * }
   1338  * ]|
   1339  * The only pieces which have to be manually provided are the definitions of
   1340  * the instance and class structure and the definitions of the instance and
   1341  * class init functions.
   1342  *
   1343  * Since: 2.4
   1344  */
   1345 #define G_DEFINE_TYPE_EXTENDED(TN, t_n, T_P, _f_, _C_)	    _G_DEFINE_TYPE_EXTENDED_BEGIN (TN, t_n, T_P, _f_) {_C_;} _G_DEFINE_TYPE_EXTENDED_END()
   1346 
   1347 /**
   1348  * G_IMPLEMENT_INTERFACE:
   1349  * @TYPE_IFACE: The #GType of the interface to add
   1350  * @iface_init: The interface init function
   1351  *
   1352  * A convenience macro to ease interface addition in the @_C_ section
   1353  * of G_DEFINE_TYPE_WITH_CODE() or G_DEFINE_ABSTRACT_TYPE_WITH_CODE().
   1354  * See G_DEFINE_TYPE_EXTENDED() for an example.
   1355  *
   1356  * Note that this macro can only be used together with the G_DEFINE_TYPE_*
   1357  * macros, since it depends on variable names from those macros.
   1358  *
   1359  * Since: 2.4
   1360  */
   1361 #define G_IMPLEMENT_INTERFACE(TYPE_IFACE, iface_init)       { \
   1362   const GInterfaceInfo g_implement_interface_info = { \
   1363     (GInterfaceInitFunc) iface_init, NULL, NULL \
   1364   }; \
   1365   g_type_add_interface_static (g_define_type_id, TYPE_IFACE, &g_implement_interface_info); \
   1366 }
   1367 
   1368 #define _G_DEFINE_TYPE_EXTENDED_BEGIN(TypeName, type_name, TYPE_PARENT, flags) \
   1369 \
   1370 static void     type_name##_init              (TypeName        *self); \
   1371 static void     type_name##_class_init        (TypeName##Class *klass); \
   1372 static gpointer type_name##_parent_class = NULL; \
   1373 static void     type_name##_class_intern_init (gpointer klass) \
   1374 { \
   1375   type_name##_parent_class = g_type_class_peek_parent (klass); \
   1376   type_name##_class_init ((TypeName##Class*) klass); \
   1377 } \
   1378 \
   1379 GType \
   1380 type_name##_get_type (void) \
   1381 { \
   1382   static volatile gsize g_define_type_id__volatile = 0; \
   1383   if (g_once_init_enter (&g_define_type_id__volatile))  \
   1384     { \
   1385       GType g_define_type_id = \
   1386         g_type_register_static_simple (TYPE_PARENT, \
   1387                                        g_intern_static_string (#TypeName), \
   1388                                        sizeof (TypeName##Class), \
   1389                                        (GClassInitFunc) type_name##_class_intern_init, \
   1390                                        sizeof (TypeName), \
   1391                                        (GInstanceInitFunc) type_name##_init, \
   1392                                        (GTypeFlags) flags); \
   1393       { /* custom code follows */
   1394 #define _G_DEFINE_TYPE_EXTENDED_END()	\
   1395         /* following custom code */	\
   1396       }					\
   1397       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id); \
   1398     }					\
   1399   return g_define_type_id__volatile;	\
   1400 } /* closes type_name##_get_type() */
   1401 
   1402 
   1403 /* --- protected (for fundamental type implementations) --- */
   1404 GTypePlugin*	 g_type_get_plugin		(GType		     type);
   1405 GTypePlugin*	 g_type_interface_get_plugin	(GType		     instance_type,
   1406 						 GType               interface_type);
   1407 GType		 g_type_fundamental_next	(void);
   1408 GType		 g_type_fundamental		(GType		     type_id);
   1409 GTypeInstance*   g_type_create_instance         (GType               type);
   1410 void             g_type_free_instance           (GTypeInstance      *instance);
   1411 
   1412 void		 g_type_add_class_cache_func    (gpointer	     cache_data,
   1413 						 GTypeClassCacheFunc cache_func);
   1414 void		 g_type_remove_class_cache_func (gpointer	     cache_data,
   1415 						 GTypeClassCacheFunc cache_func);
   1416 void             g_type_class_unref_uncached    (gpointer            g_class);
   1417 
   1418 void             g_type_add_interface_check     (gpointer	         check_data,
   1419 						 GTypeInterfaceCheckFunc check_func);
   1420 void             g_type_remove_interface_check  (gpointer	         check_data,
   1421 						 GTypeInterfaceCheckFunc check_func);
   1422 
   1423 GTypeValueTable* g_type_value_table_peek        (GType		     type);
   1424 
   1425 
   1426 /*< private >*/
   1427 gboolean	 g_type_check_instance          (GTypeInstance      *instance) G_GNUC_PURE;
   1428 GTypeInstance*   g_type_check_instance_cast     (GTypeInstance      *instance,
   1429 						 GType               iface_type);
   1430 gboolean         g_type_check_instance_is_a	(GTypeInstance      *instance,
   1431 						 GType               iface_type) G_GNUC_PURE;
   1432 GTypeClass*      g_type_check_class_cast        (GTypeClass         *g_class,
   1433 						 GType               is_a_type);
   1434 gboolean         g_type_check_class_is_a        (GTypeClass         *g_class,
   1435 						 GType               is_a_type) G_GNUC_PURE;
   1436 gboolean	 g_type_check_is_value_type     (GType		     type) G_GNUC_CONST;
   1437 gboolean	 g_type_check_value             (GValue		    *value) G_GNUC_PURE;
   1438 gboolean	 g_type_check_value_holds	(GValue		    *value,
   1439 						 GType		     type) G_GNUC_PURE;
   1440 gboolean         g_type_test_flags              (GType               type,
   1441 						 guint               flags) G_GNUC_CONST;
   1442 
   1443 
   1444 /* --- debugging functions --- */
   1445 G_CONST_RETURN gchar* g_type_name_from_instance	(GTypeInstance	*instance);
   1446 G_CONST_RETURN gchar* g_type_name_from_class	(GTypeClass	*g_class);
   1447 
   1448 
   1449 /* --- internal functions --- */
   1450 G_GNUC_INTERNAL void    g_value_c_init          (void); /* sync with gvalue.c */
   1451 G_GNUC_INTERNAL void    g_value_types_init      (void); /* sync with gvaluetypes.c */
   1452 G_GNUC_INTERNAL void    g_enum_types_init       (void); /* sync with genums.c */
   1453 G_GNUC_INTERNAL void    g_param_type_init       (void); /* sync with gparam.c */
   1454 G_GNUC_INTERNAL void    g_boxed_type_init       (void); /* sync with gboxed.c */
   1455 G_GNUC_INTERNAL void    g_object_type_init      (void); /* sync with gobject.c */
   1456 G_GNUC_INTERNAL void    g_param_spec_types_init (void); /* sync with gparamspecs.c */
   1457 G_GNUC_INTERNAL void    g_value_transforms_init (void); /* sync with gvaluetransform.c */
   1458 G_GNUC_INTERNAL void    g_signal_init           (void); /* sync with gsignal.c */
   1459 
   1460 
   1461 /* --- implementation bits --- */
   1462 #ifndef G_DISABLE_CAST_CHECKS
   1463 #  define _G_TYPE_CIC(ip, gt, ct) \
   1464     ((ct*) g_type_check_instance_cast ((GTypeInstance*) ip, gt))
   1465 #  define _G_TYPE_CCC(cp, gt, ct) \
   1466     ((ct*) g_type_check_class_cast ((GTypeClass*) cp, gt))
   1467 #else /* G_DISABLE_CAST_CHECKS */
   1468 #  define _G_TYPE_CIC(ip, gt, ct)       ((ct*) ip)
   1469 #  define _G_TYPE_CCC(cp, gt, ct)       ((ct*) cp)
   1470 #endif /* G_DISABLE_CAST_CHECKS */
   1471 #define _G_TYPE_CHI(ip)			(g_type_check_instance ((GTypeInstance*) ip))
   1472 #define _G_TYPE_CHV(vl)			(g_type_check_value ((GValue*) vl))
   1473 #define _G_TYPE_IGC(ip, gt, ct)         ((ct*) (((GTypeInstance*) ip)->g_class))
   1474 #define _G_TYPE_IGI(ip, gt, ct)         ((ct*) g_type_interface_peek (((GTypeInstance*) ip)->g_class, gt))
   1475 #ifdef	__GNUC__
   1476 #  define _G_TYPE_CIT(ip, gt)             (G_GNUC_EXTENSION ({ \
   1477   GTypeInstance *__inst = (GTypeInstance*) ip; GType __t = gt; gboolean __r; \
   1478   if (__inst && __inst->g_class && __inst->g_class->g_type == __t) \
   1479     __r = TRUE; \
   1480   else \
   1481     __r = g_type_check_instance_is_a (__inst, __t); \
   1482   __r; \
   1483 }))
   1484 #  define _G_TYPE_CCT(cp, gt)             (G_GNUC_EXTENSION ({ \
   1485   GTypeClass *__class = (GTypeClass*) cp; GType __t = gt; gboolean __r; \
   1486   if (__class && __class->g_type == __t) \
   1487     __r = TRUE; \
   1488   else \
   1489     __r = g_type_check_class_is_a (__class, __t); \
   1490   __r; \
   1491 }))
   1492 #  define _G_TYPE_CVH(vl, gt)             (G_GNUC_EXTENSION ({ \
   1493   GValue *__val = (GValue*) vl; GType __t = gt; gboolean __r; \
   1494   if (__val && __val->g_type == __t) \
   1495     __r = TRUE; \
   1496   else \
   1497     __r = g_type_check_value_holds (__val, __t); \
   1498   __r; \
   1499 }))
   1500 #else  /* !__GNUC__ */
   1501 #  define _G_TYPE_CIT(ip, gt)             (g_type_check_instance_is_a ((GTypeInstance*) ip, gt))
   1502 #  define _G_TYPE_CCT(cp, gt)             (g_type_check_class_is_a ((GTypeClass*) cp, gt))
   1503 #  define _G_TYPE_CVH(vl, gt)             (g_type_check_value_holds ((GValue*) vl, gt))
   1504 #endif /* !__GNUC__ */
   1505 /**
   1506  * G_TYPE_FLAG_RESERVED_ID_BIT:
   1507  *
   1508  * A bit in the type number that's supposed to be left untouched.
   1509  */
   1510 #define	G_TYPE_FLAG_RESERVED_ID_BIT	((GType) (1 << 0))
   1511 extern GTypeDebugFlags			_g_type_debug_flags;
   1512 
   1513 G_END_DECLS
   1514 
   1515 #endif /* __G_TYPE_H__ */
   1516