Enums and Flags

Enums and Flags — Enumeration and flags types

Synopsis

#include <glib-object.h>


            GEnumClass;
            GFlagsClass;
#define     G_ENUM_CLASS_TYPE               (class)
#define     G_ENUM_CLASS_TYPE_NAME          (class)
#define     G_TYPE_IS_ENUM                  (type)
#define     G_ENUM_CLASS                    (class)
#define     G_IS_ENUM_CLASS                 (class)
#define     G_TYPE_IS_FLAGS                 (type)
#define     G_FLAGS_CLASS                   (class)
#define     G_IS_FLAGS_CLASS                (class)
#define     G_FLAGS_CLASS_TYPE              (class)
#define     G_FLAGS_CLASS_TYPE_NAME         (class)
            GEnumValue;
            GFlagsValue;
GEnumValue* g_enum_get_value                (GEnumClass *enum_class,
                                             gint value);
GEnumValue* g_enum_get_value_by_name        (GEnumClass *enum_class,
                                             const gchar *name);
GEnumValue* g_enum_get_value_by_nick        (GEnumClass *enum_class,
                                             const gchar *nick);
GFlagsValue* g_flags_get_first_value        (GFlagsClass *flags_class,
                                             guint value);
GFlagsValue* g_flags_get_value_by_name      (GFlagsClass *flags_class,
                                             const gchar *name);
GFlagsValue* g_flags_get_value_by_nick      (GFlagsClass *flags_class,
                                             const gchar *nick);
GType       g_enum_register_static          (const gchar *name,
                                             const GEnumValue *const_static_values);
GType       g_flags_register_static         (const gchar *name,
                                             const GFlagsValue *const_static_values);
void        g_enum_complete_type_info       (GType g_enum_type,
                                             GTypeInfo *info,
                                             const GEnumValue *const_values);
void        g_flags_complete_type_info      (GType g_flags_type,
                                             GTypeInfo *info,
                                             const GFlagsValue *const_values);

Description

Details

GEnumClass

typedef struct {
  GTypeClass  g_type_class;

  gint	      minimum;
  gint	      maximum;
  guint	      n_values;
  GEnumValue *values;
} GEnumClass;

The class of an enumeration type holds information about its possible values.

GTypeClass g_type_class;
gint minimum;the smallest possible value.
gint maximum;the largest possible value.
guint n_values;the number of possible values.
GEnumValue *values;an array of GEnumValue structs describing the individual values.

GFlagsClass

typedef struct {
  GTypeClass   g_type_class;
  
  guint	       mask;
  guint	       n_values;
  GFlagsValue *values;
} GFlagsClass;

The class of a flags type holds information about its possible values.

GTypeClass g_type_class;
guint mask;a mask covering all possible values.
guint n_values;the number of possible values.
GFlagsValue *values;an array of GFlagsValue structs describing the individual values.

G_ENUM_CLASS_TYPE()

#define G_ENUM_CLASS_TYPE(class)       (G_TYPE_FROM_CLASS (class))

Returns the type identifier from a given GEnumClass structure.

class :a GEnumClass

G_ENUM_CLASS_TYPE_NAME()

#define G_ENUM_CLASS_TYPE_NAME(class)  (g_type_name (G_ENUM_CLASS_TYPE (class)))

Returns the static type name from a given GEnumClass structure.

class :a GEnumClass

G_TYPE_IS_ENUM()

#define G_TYPE_IS_ENUM(type)	       (G_TYPE_FUNDAMENTAL (type) == G_TYPE_ENUM)

Returns whether type "is a" G_TYPE_ENUM.

type :a GType ID.

G_ENUM_CLASS()

#define G_ENUM_CLASS(class)	       (G_TYPE_CHECK_CLASS_CAST ((class), G_TYPE_ENUM, GEnumClass))

Casts a derived GEnumClass structure into a GEnumClass structure.

class :a valid GEnumClass

G_IS_ENUM_CLASS()

#define G_IS_ENUM_CLASS(class)	       (G_TYPE_CHECK_CLASS_TYPE ((class), G_TYPE_ENUM))

Checks whether class "is a" valid GEnumClass structure of type G_TYPE_ENUM or derived.

class :a GEnumClass

G_TYPE_IS_FLAGS()

#define G_TYPE_IS_FLAGS(type)	       (G_TYPE_FUNDAMENTAL (type) == G_TYPE_FLAGS)

Returns whether type "is a" G_TYPE_FLAGS.

type :a GType ID.

G_FLAGS_CLASS()

#define G_FLAGS_CLASS(class)	       (G_TYPE_CHECK_CLASS_CAST ((class), G_TYPE_FLAGS, GFlagsClass))

Casts a derived GFlagsClass structure into a GFlagsClass structure.

class :a valid GFlagsClass

G_IS_FLAGS_CLASS()

#define G_IS_FLAGS_CLASS(class)        (G_TYPE_CHECK_CLASS_TYPE ((class), G_TYPE_FLAGS))

Checks whether class "is a" valid GFlagsClass structure of type G_TYPE_FLAGS or derived.

class :a GFlagsClass

G_FLAGS_CLASS_TYPE()

#define G_FLAGS_CLASS_TYPE(class)      (G_TYPE_FROM_CLASS (class))

Returns the type identifier from a given GFlagsClass structure.

class :a GFlagsClass

G_FLAGS_CLASS_TYPE_NAME()

#define G_FLAGS_CLASS_TYPE_NAME(class) (g_type_name (G_FLAGS_TYPE (class)))

Returns the static type name from a given GFlagsClass structure.

class :a GFlagsClass

GEnumValue

typedef struct {
  gint	 value;
  gchar *value_name;
  gchar *value_nick;
} GEnumValue;

A structure which contains a single enum value, it's name, and it's nickname.

gint value;the enum value
gchar *value_name;the name of the value
gchar *value_nick;the nickname of the value

GFlagsValue

typedef struct {
  guint	 value;
  gchar *value_name;
  gchar *value_nick;
} GFlagsValue;

A structure which contains a single flags value, it's name, and it's nickname.

guint value;the flags value
gchar *value_name;the name of the value
gchar *value_nick;the nickname of the value

g_enum_get_value ()

GEnumValue* g_enum_get_value                (GEnumClass *enum_class,
                                             gint value);

Returns the GEnumValue for a value.

enum_class :a GEnumClass
value :the value to look up
Returns :the GEnumValue for value, or NULL if value is not a member of the enumeration

g_enum_get_value_by_name ()

GEnumValue* g_enum_get_value_by_name        (GEnumClass *enum_class,
                                             const gchar *name);

Looks up a GEnumValue by name.

enum_class :a GEnumClass
name :the name to look up
Returns :the GEnumValue with name name, or NULL if the enumeration doesn' t have a member with that name

g_enum_get_value_by_nick ()

GEnumValue* g_enum_get_value_by_nick        (GEnumClass *enum_class,
                                             const gchar *nick);

Looks up a GEnumValue by nickname.

enum_class :a GEnumClass
nick :the nickname to look up
Returns :the GEnumValue with nickname nick, or NULL if the enumeration doesn' t have a member with that nickname

g_flags_get_first_value ()

GFlagsValue* g_flags_get_first_value        (GFlagsClass *flags_class,
                                             guint value);

Returns the first GFlagsValue which is set in value.

flags_class :a GFlagsClass
value :the value
Returns :the first GFlagsValue which is set in value, or NULL if none is set

g_flags_get_value_by_name ()

GFlagsValue* g_flags_get_value_by_name      (GFlagsClass *flags_class,
                                             const gchar *name);

Looks up a GFlagsValue by name.

flags_class :a GFlagsClass
name :the name to look up
Returns :the GFlagsValue with name name, or NULL if there is no flag with that name

g_flags_get_value_by_nick ()

GFlagsValue* g_flags_get_value_by_nick      (GFlagsClass *flags_class,
                                             const gchar *nick);

Looks up a GFlagsValue by nickname.

flags_class :a GFlagsClass
nick :the nickname to look up
Returns :the GFlagsValue with nickname nick, or NULL if there is no flag with that nickname

g_enum_register_static ()

GType       g_enum_register_static          (const gchar *name,
                                             const GEnumValue *const_static_values);

Registers a new static enumeration type with the name name.

It is normally more convenient to let glib-mkenums generate a my_enum_get_type() function from a usual C enumeration definition than to write one yourself using g_enum_register_static().

name :A nul-terminated string used as the name of the new type.
const_static_values :An array of GEnumValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0.
Returns :The new type identifier.

g_flags_register_static ()

GType       g_flags_register_static         (const gchar *name,
                                             const GFlagsValue *const_static_values);

Registers a new static flags type with the name name.

It is normally more convenient to let glib-mkenums generate a my_flags_get_type() function from a usual C enumeration definition than to write one yourself using g_flags_register_static().

name :A nul-terminated string used as the name of the new type.
const_static_values :An array of GFlagsValue structs for the possible flags values. The array is terminated by a struct with all members being 0.
Returns :The new type identifier.

g_enum_complete_type_info ()

void        g_enum_complete_type_info       (GType g_enum_type,
                                             GTypeInfo *info,
                                             const GEnumValue *const_values);

This function is meant to be called from the complete_type_info() function of a GTypePlugin implementation, as in the following example:

static void
my_enum_complete_type_info (GTypePlugin     *plugin,
                            GType            g_type,
                            GTypeInfo       *info,
                            GTypeValueTable *value_table)
{
  static const GEnumValue values[] = {
    { MY_ENUM_FOO, "MY_ENUM_FOO", "foo" },
    { MY_ENUM_BAR, "MY_ENUM_BAR", "bar" },
    { 0, NULL, NULL }
  };  
   
  g_enum_complete_type_info (type, info, values);  
}

g_enum_type :the type identifier of the type being completed
info :the GTypeInfo struct to be filled in
const_values :An array of GEnumValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0.

g_flags_complete_type_info ()

void        g_flags_complete_type_info      (GType g_flags_type,
                                             GTypeInfo *info,
                                             const GFlagsValue *const_values);

This function is meant to be called from the complete_type_info() function of a GTypePlugin implementation, see the example for g_enumeration_complete_type_info() above.

g_flags_type :the type identifier of the type being completed
info :the GTypeInfo struct to be filled in
const_values :An array of GFlagsValue structs for the possible enumeration values. The array is terminated by a struct with all members being 0.