G_TYPE_IS_PARAM()

#define G_TYPE_IS_PARAM(type)		(G_TYPE_FUNDAMENTAL (type) == G_TYPE_PARAM)

Returns whether type "is a" G_TYPE_PARAM.

G_PARAM_SPEC()

#define G_PARAM_SPEC(pspec)		(G_TYPE_CHECK_INSTANCE_CAST ((pspec), G_TYPE_PARAM, GParamSpec))

Casts a derived GParamSpec object (e.g. of type GParamSpecInt) into a GParamSpec object.

G_IS_PARAM_SPEC()

#define G_IS_PARAM_SPEC(pspec)		(G_TYPE_CHECK_INSTANCE_TYPE ((pspec), G_TYPE_PARAM))

Checks whether pspec "is a" valid GParamSpec structure of type G_TYPE_PARAM or derived.

G_PARAM_SPEC_CLASS()

#define G_PARAM_SPEC_CLASS(pclass)      (G_TYPE_CHECK_CLASS_CAST ((pclass), G_TYPE_PARAM, GParamSpecClass))

Casts a derived GParamSpecClass structure into a GParamSpecClass structure.

G_IS_PARAM_SPEC_CLASS()

#define G_IS_PARAM_SPEC_CLASS(pclass)   (G_TYPE_CHECK_CLASS_TYPE ((pclass), G_TYPE_PARAM))

Checks whether pclass "is a" valid GParamSpecClass structure of type G_TYPE_PARAM or derived.

G_PARAM_SPEC_GET_CLASS()

#define G_PARAM_SPEC_GET_CLASS(pspec)	(G_TYPE_INSTANCE_GET_CLASS ((pspec), G_TYPE_PARAM, GParamSpecClass))

Retrieves the GParamSpecClass of a GParamSpec.

G_PARAM_SPEC_TYPE()

#define G_PARAM_SPEC_TYPE(pspec)	(G_TYPE_FROM_INSTANCE (pspec))

Retrieves the GType of this pspec.

G_PARAM_SPEC_TYPE_NAME()

#define G_PARAM_SPEC_TYPE_NAME(pspec)	(g_type_name (G_PARAM_SPEC_TYPE (pspec)))

Retrieves the GType name of this pspec.

G_PARAM_SPEC_VALUE_TYPE()

#define	G_PARAM_SPEC_VALUE_TYPE(pspec)	(G_PARAM_SPEC (pspec)->value_type)

Retrieves the GType to initialize a GValue for this parameter.

GParamSpec

typedef struct {
  GTypeInstance  g_type_instance;

  gchar         *name;
  GParamFlags    flags;
  GType		 value_type;
  GType		 owner_type;	/* class or interface using this property */
} GParamSpec;

All fields of the GParamSpec struct are private and should not be used directly, except for the following:

GParamSpecClass

typedef struct {
  GTypeClass      g_type_class;

  GType		  value_type;

  void	        (*finalize)		(GParamSpec   *pspec);

  /* GParam methods */
  void          (*value_set_default)    (GParamSpec   *pspec,
					 GValue       *value);
  gboolean      (*value_validate)       (GParamSpec   *pspec,
					 GValue       *value);
  gint          (*values_cmp)           (GParamSpec   *pspec,
					 const GValue *value1,
					 const GValue *value2);
} GParamSpecClass;

The class structure for the GParamSpec type. Normally, GParamSpec classes are filled by g_param_type_register_static().

enum GParamFlags

typedef enum
{
  G_PARAM_READABLE            = 1 << 0,
  G_PARAM_WRITABLE            = 1 << 1,
  G_PARAM_CONSTRUCT	      = 1 << 2,
  G_PARAM_CONSTRUCT_ONLY      = 1 << 3,
  G_PARAM_LAX_VALIDATION      = 1 << 4,
  G_PARAM_STATIC_NAME	      = 1 << 5,
#ifndef G_DISABLE_DEPRECATED
  G_PARAM_PRIVATE	      = G_PARAM_STATIC_NAME,
#endif
  G_PARAM_STATIC_NICK	      = 1 << 6,
  G_PARAM_STATIC_BLURB	      = 1 << 7
} GParamFlags;

Through the GParamFlags flag values, certain aspects of parameters can be configured.

G_PARAM_READWRITE

#define	G_PARAM_READWRITE	(G_PARAM_READABLE | G_PARAM_WRITABLE)

GParamFlags value alias for G_PARAM_READABLE | G_PARAM_WRITABLE.

G_PARAM_STATIC_STRINGS

#define	G_PARAM_STATIC_STRINGS (G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB)

GParamFlags value alias for G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB.

G_PARAM_MASK

#define	G_PARAM_MASK		(0x000000ff)

Mask containing the bits of GParamSpec.flags which are reserved for GLib.

G_PARAM_USER_SHIFT

#define	G_PARAM_USER_SHIFT	(8)

Minimum shift count to be used for user defined flags, to be stored in GParamSpec.flags.

g_param_spec_ref ()

GParamSpec*         g_param_spec_ref                    (GParamSpec *pspec);

Increments the reference count of pspec.

g_param_spec_unref ()

void                g_param_spec_unref                  (GParamSpec *pspec);

Decrements the reference count of a pspec.

g_param_spec_sink ()

void                g_param_spec_sink                   (GParamSpec *pspec);

The initial reference count of a newly created GParamSpec is 1, even though no one has explicitly called g_param_spec_ref() on it yet. So the initial reference count is flagged as "floating", until someone calls g_param_spec_ref (pspec); g_param_spec_sink (pspec); in sequence on it, taking over the initial reference count (thus ending up with a pspec that has a reference count of 1 still, but is not flagged "floating" anymore).

g_param_spec_ref_sink ()

GParamSpec*         g_param_spec_ref_sink               (GParamSpec *pspec);

Convenience function to ref and sink a GParamSpec.

Since 2.10

g_param_value_set_default ()

void                g_param_value_set_default           (GParamSpec *pspec,
                                                         GValue *value);

Sets value to its default value as specified in pspec.

g_param_value_defaults ()

gboolean            g_param_value_defaults              (GParamSpec *pspec,
                                                         GValue *value);

Checks whether value contains the default value as specified in pspec.

g_param_value_validate ()

gboolean            g_param_value_validate              (GParamSpec *pspec,
                                                         GValue *value);

Ensures that the contents of value comply with the specifications set out by pspec. For example, a GParamSpecInt might require that integers stored in value may not be smaller than -42 and not be greater than +42. If value contains an integer outside of this range, it is modified accordingly, so the resulting value will fit into the range -42 .. +42.

g_param_value_convert ()

gboolean            g_param_value_convert               (GParamSpec *pspec,
                                                         const GValue *src_value,
                                                         GValue *dest_value,
                                                         gboolean strict_validation);

Transforms src_value into dest_value if possible, and then validates dest_value, in order for it to conform to pspec. If strict_validation is TRUE this function will only succeed if the transformed dest_value complied to pspec without modifications. See also g_value_type_transformable(), g_value_transform() and g_param_value_validate().

g_param_values_cmp ()

gint                g_param_values_cmp                  (GParamSpec *pspec,
                                                         const GValue *value1,
                                                         const GValue *value2);

Compares value1 with value2 according to pspec, and return -1, 0 or +1, if value1 is found to be less than, equal to or greater than value2, respectively.

g_param_spec_get_name ()

const gchar*        g_param_spec_get_name               (GParamSpec *pspec);

Returns the name of a GParamSpec.

g_param_spec_get_nick ()

const gchar*        g_param_spec_get_nick               (GParamSpec *pspec);

Returns the nickname of a GParamSpec.

g_param_spec_get_blurb ()

const gchar*        g_param_spec_get_blurb              (GParamSpec *pspec);

Returns the short description of a GParamSpec.

g_param_spec_get_qdata ()

gpointer            g_param_spec_get_qdata              (GParamSpec *pspec,
                                                         GQuark quark);

Gets back user data pointers stored via g_param_spec_set_qdata().

g_param_spec_set_qdata ()

void                g_param_spec_set_qdata              (GParamSpec *pspec,
                                                         GQuark quark,
                                                         gpointer data);

Sets an opaque, named pointer on a GParamSpec. The name is specified through a GQuark (retrieved e.g. via g_quark_from_static_string()), and the pointer can be gotten back from the pspec with g_param_spec_get_qdata(). Setting a previously set user data pointer, overrides (frees) the old pointer set, using NULL as pointer essentially removes the data stored.

g_param_spec_set_qdata_full ()

void                g_param_spec_set_qdata_full         (GParamSpec *pspec,
                                                         GQuark quark,
                                                         gpointer data,
                                                         GDestroyNotify destroy);

This function works like g_param_spec_set_qdata(), but in addition, a void (*destroy) (gpointer) function may be specified which is called with data as argument when the pspec is finalized, or the data is being overwritten by a call to g_param_spec_set_qdata() with the same quark.

g_param_spec_steal_qdata ()

gpointer            g_param_spec_steal_qdata            (GParamSpec *pspec,
                                                         GQuark quark);

Gets back user data pointers stored via g_param_spec_set_qdata() and removes the data from pspec without invoking it's destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier.

g_param_spec_get_redirect_target ()

GParamSpec*         g_param_spec_get_redirect_target    (GParamSpec *pspec);

If the paramspec redirects operations to another paramspec, returns that paramspec. Redirect is used typically for providing a new implementation of a property in a derived type while preserving all the properties from the parent type. Redirection is established by creating a property of type GParamSpecOverride. See g_object_override_property() for an example of the use of this capability.

Since 2.4

g_param_spec_internal ()

gpointer            g_param_spec_internal               (GType param_type,
                                                         const gchar *name,
                                                         const gchar *nick,
                                                         const gchar *blurb,
                                                         GParamFlags flags);

Creates a new GParamSpec instance.

A property name consists of segments consisting of ASCII letters and digits, separated by either the '-' or '_' character. The first character of a property name must be a letter. Names which violate these rules lead to undefined behaviour.

When creating and looking up a GParamSpec, either separator can be used, but they cannot be mixed. Using '-' is considerably more efficient and in fact required when using property names as detail strings for signals.

GParamSpecTypeInfo

typedef struct {
  /* type system portion */
  guint16         instance_size;                               /* obligatory */
  guint16         n_preallocs;                                 /* optional */
  void		(*instance_init)	(GParamSpec   *pspec); /* optional */

  /* class portion */
  GType           value_type;				       /* obligatory */
  void          (*finalize)             (GParamSpec   *pspec); /* optional */
  void          (*value_set_default)    (GParamSpec   *pspec,  /* recommended */
					 GValue       *value);
  gboolean      (*value_validate)       (GParamSpec   *pspec,  /* optional */
					 GValue       *value);
  gint          (*values_cmp)           (GParamSpec   *pspec,  /* recommended */
					 const GValue *value1,
					 const GValue *value2);
} GParamSpecTypeInfo;

This structure is used to provide the type system with the information required to initialize and destruct (finalize) a parameter's class and instances thereof. The initialized structure is passed to the g_param_type_register_static() The type system will perform a deep copy of this structure, so it's memory does not need to be persistent across invocation of g_param_type_register_static().

g_param_type_register_static ()

GType               g_param_type_register_static        (const gchar *name,
                                                         const GParamSpecTypeInfo *pspec_info);

Registers name as the name of a new static type derived from G_TYPE_PARAM. The type system uses the information contained in the GParamSpecTypeInfo structure pointed to by info to manage the GParamSpec type and its instances.

GParamSpecPool

typedef struct _GParamSpecPool GParamSpecPool;

A GParamSpecPool maintains a collection of GParamSpecs which can be quickly accessed by owner and name. The implementation of the GObject property system uses such a pool to store the GParamSpecs of the properties all object types.

g_param_spec_pool_new ()

GParamSpecPool*     g_param_spec_pool_new               (gboolean type_prefixing);

Creates a new GParamSpecPool.

If type_prefixing is TRUE, lookups in the newly created pool will allow to specify the owner as a colon-separated prefix of the property name, like "GtkContainer:border-width". This feature is deprecated, so you should always set type_prefixing to FALSE.

g_param_spec_pool_insert ()

void                g_param_spec_pool_insert            (GParamSpecPool *pool,
                                                         GParamSpec *pspec,
                                                         GType owner_type);

Inserts a GParamSpec in the pool.

g_param_spec_pool_remove ()

void                g_param_spec_pool_remove            (GParamSpecPool *pool,
                                                         GParamSpec *pspec);

Removes a GParamSpec from the pool.

g_param_spec_pool_lookup ()

GParamSpec*         g_param_spec_pool_lookup            (GParamSpecPool *pool,
                                                         const gchar *param_name,
                                                         GType owner_type,
                                                         gboolean walk_ancestors);

Looks up a GParamSpec in the pool.

g_param_spec_pool_list ()

GParamSpec**        g_param_spec_pool_list              (GParamSpecPool *pool,
                                                         GType owner_type,
                                                         guint *n_pspecs_p);

Gets an array of all GParamSpecs owned by owner_type in the pool.

g_param_spec_pool_list_owned ()

GList*              g_param_spec_pool_list_owned        (GParamSpecPool *pool,
                                                         GType owner_type);

Gets an GList of all GParamSpecs owned by owner_type in the pool.