GObject Reference Manual | |||
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GParamSpec is an object structure that encapsulates the meta data required to specify parameters, such as e.g. GObject properties.
#define G_TYPE_IS_PARAM(type) (G_TYPE_FUNDAMENTAL (type) == G_TYPE_PARAM) |
Returns whether type "is a" G_TYPE_PARAM.
type : | a GType ID |
#define G_PARAM_SPEC(pspec) (G_TYPE_CHECK_INSTANCE_CAST ((pspec), G_TYPE_PARAM, GParamSpec)) |
Cast a derived GParamSpec object (e.g. of type GParamSpecInt) into a GParamSpec object.
pspec : | a valid GParamSpec |
#define G_IS_PARAM_SPEC(pspec) (G_TYPE_CHECK_INSTANCE_TYPE ((pspec), G_TYPE_PARAM)) |
Check whether pspec "is a" valid GParamSpec structure of type G_TYPE_PARAM or derived.
pspec : |
#define G_PARAM_SPEC_CLASS(pclass) (G_TYPE_CHECK_CLASS_CAST ((pclass), G_TYPE_PARAM, GParamSpecClass)) |
Cast a derived GParamSpecClass structure into a GParamSpecClass structure.
pclass : | a valid GParamSpecClass |
#define G_IS_PARAM_SPEC_CLASS(pclass) (G_TYPE_CHECK_CLASS_TYPE ((pclass), G_TYPE_PARAM)) |
Check whether pclass "is a" valid GParamSpecClass structure of type G_TYPE_PARAM or derived.
pclass : |
#define G_PARAM_SPEC_GET_CLASS(pspec) (G_TYPE_INSTANCE_GET_CLASS ((pspec), G_TYPE_PARAM, GParamSpecClass)) |
Retrieve the GParamSpecClass of a GParamSpec.
pspec : | a valid GParamSpec |
#define G_PARAM_SPEC_TYPE(pspec) (G_TYPE_FROM_INSTANCE (pspec)) |
Retrive the GType of this pspec.
pspec : | a valid GParamSpec |
#define G_PARAM_SPEC_TYPE_NAME(pspec) (g_type_name (G_PARAM_SPEC_TYPE (pspec))) |
Retrive the GType name of this pspec.
pspec : | a valid GParamSpec |
#define G_PARAM_SPEC_VALUE_TYPE(pspec) (G_PARAM_SPEC (pspec)->value_type) |
Retrive the GType to intiialize a GValue for this parameter.
pspec : | a valid GParamSpec |
struct GParamSpec { GTypeInstance g_type_instance; gchar *name; GParamFlags flags; GType value_type; GType owner_type; /* class using this property */ /*< private >*/ gchar *_nick; gchar *_blurb; GData *qdata; guint ref_count; guint param_id; /* sort-criteria */ }; |
GTypeInstance g_type_instance | private GTypeInstance portion |
gchar *name | name of this parameter |
GParamFlags flags | GParamFlags flags for this parameter |
GType value_type | the GValue type for this parameter |
GType owner_type | GType type that uses (introduces) this paremeter |
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_PRIVATE = 1 << 5 } GParamFlags; |
Through the GParamFlags flag values, certain aspects of parameters can be configured.
G_PARAM_READABLE | the parameter is readable |
G_PARAM_WRITABLE | the parameter is writable |
G_PARAM_CONSTRUCT | the parameter will be set upon object construction |
G_PARAM_CONSTRUCT_ONLY | the parameter will only be set upon object construction |
G_PARAM_LAX_VALIDATION | upon parameter conversion (see g_param_value_convert()) strict validation is not required |
G_PARAM_PRIVATE |
#define G_PARAM_READWRITE (G_PARAM_READABLE | G_PARAM_WRITABLE) |
GParamFlags value alias for G_PARAM_READABLE | G_PARAM_WRITABLE.
#define G_PARAM_MASK (0x000000ff) |
Mask containing the bits of GParamSpec.flags which are reserved for GLib.
#define G_PARAM_USER_SHIFT (8) |
Minimum shift count to be used for user defined flags, to be stored in GParamSpec.flags.
GParamSpec* g_param_spec_ref (GParamSpec *pspec); |
Increment the reference count of pspec.
pspec : | a valid GParamSpec |
Returns : | the GParamSpec that was passed into this function |
void g_param_spec_unref (GParamSpec *pspec); |
Decrement the reference count of a pspec.
pspec : | a valid GParamSpec |
void g_param_spec_sink (GParamSpec *pspec); |
The initial reference count of a newly created GParamSpec is 1, eventhough no one has explicitely called g_param_spec_ref() on it yet. So the einital reference count is flagged as "floating", untill 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).
pspec : | a valid GParamSpec |
void g_param_value_set_default (GParamSpec *pspec, GValue *value); |
Set value to its default value as specified in pspec.
pspec : | a valid GParamSpec |
value : | a GValue of correct type for pspec |
gboolean g_param_value_defaults (GParamSpec *pspec, GValue *value); |
Check whether value contains the default value as specified in pspec.
pspec : | a valid GParamSpec |
value : | a GValue of correct type for pspec |
Returns : | whether value contains the canonical defualt for this pspec |
gboolean g_param_value_validate (GParamSpec *pspec, GValue *value); |
Ensure 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.
pspec : | a valid GParamSpec |
value : | a GValue of correct type for pspec |
Returns : | whether modifying value was necessary to ensure validity |
gboolean g_param_value_convert (GParamSpec *pspec, const GValue *src_value, GValue *dest_value, gboolean strict_validation); |
This function 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 suceed if the transformed dest_value complied to pspec without modifications. See also g_value_type_transformable(), g_value_transform() and g_param_value_validate().
pspec : | a valid GParamSpec |
src_value : | souce GValue |
dest_value : | destination GValue of correct type for pspec |
strict_validation : | $TRUE requires dest_value to conform to pspec without modifications |
Returns : | TRUE if transformation and validation were successfull, FALSE otherwise and dest_value is left untouched. |
gint g_param_values_cmp (GParamSpec *pspec, const GValue *value1, const GValue *value2); |
Compare 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.
pspec : | a valid GParamSpec |
value1 : | a GValue of correct type for pspec |
value2 : | a GValue of correct type for pspec |
Returns : | -1, 0 or +1, for a less than, equal to or greater than result |
G_CONST_RETURN gchar* g_param_spec_get_name (GParamSpec *pspec); |
pspec : | |
Returns : |
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G_CONST_RETURN gchar* g_param_spec_get_nick (GParamSpec *pspec); |
pspec : | |
Returns : |
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G_CONST_RETURN gchar* g_param_spec_get_blurb (GParamSpec *pspec); |
pspec : | |
Returns : |
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gpointer g_param_spec_get_qdata (GParamSpec *pspec, GQuark quark); |
pspec : | |
quark : | |
Returns : |
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void g_param_spec_set_qdata (GParamSpec *pspec, GQuark quark, gpointer data); |
pspec : | |
quark : | |
data : |
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void g_param_spec_set_qdata_full (GParamSpec *pspec, GQuark quark, gpointer data, GDestroyNotify destroy); |
pspec : | |
quark : | |
data : | |
destroy : |
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gpointer g_param_spec_steal_qdata (GParamSpec *pspec, GQuark quark); |
pspec : | |
quark : | |
Returns : |
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gpointer g_param_spec_internal (GType param_type, const gchar *name, const gchar *nick, const gchar *blurb, GParamFlags flags); |
param_type : | |
name : | |
nick : | |
blurb : | |
flags : | |
Returns : |
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struct GParamSpecTypeInfo { /* 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); }; |
GType g_param_type_register_static (const gchar *name, const GParamSpecTypeInfo *pspec_info); |
name : | |
pspec_info : | |
Returns : |
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GParamSpecPool* g_param_spec_pool_new (gboolean type_prefixing); |
type_prefixing : | |
Returns : |
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void g_param_spec_pool_insert (GParamSpecPool *pool, GParamSpec *pspec, GType owner_type); |
pool : | |
pspec : | |
owner_type : |
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void g_param_spec_pool_remove (GParamSpecPool *pool, GParamSpec *pspec); |
pool : | |
pspec : |
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GParamSpec* g_param_spec_pool_lookup (GParamSpecPool *pool, const gchar *param_name, GType owner_type, gboolean walk_ancestors); |
pool : | |
param_name : | |
owner_type : | |
walk_ancestors : | |
Returns : |
GParamSpec** g_param_spec_pool_list (GParamSpecPool *pool, GType owner_type, guint *n_pspecs_p); |
pool : | |
owner_type : | |
n_pspecs_p : | |
Returns : |
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GList* g_param_spec_pool_list_owned (GParamSpecPool *pool, GType owner_type); |
pool : | |
owner_type : | |
Returns : |
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