GObject Reference Manual: Enumeration and Flag Types

## Enumeration and Flag Types Enumeration and Flag Types — Enumeration and flags types |

## Functions

#define | G_ENUM_CLASS_TYPE()
#define | G_ENUM_CLASS_TYPE_NAME()
#define | G_TYPE_IS_ENUM()
#define | G_ENUM_CLASS()
#define | G_IS_ENUM_CLASS()
#define | G_TYPE_IS_FLAGS()
#define | G_FLAGS_CLASS()
#define | G_IS_FLAGS_CLASS()
#define | G_FLAGS_CLASS_TYPE()
#define | G_FLAGS_CLASS_TYPE_NAME()
GEnumValue * | g_enum_get_value ()
GEnumValue * | g_enum_get_value_by_name ()
GEnumValue * | g_enum_get_value_by_nick ()
GFlagsValue * | g_flags_get_first_value ()
GFlagsValue * | g_flags_get_value_by_name ()
GFlagsValue * | g_flags_get_value_by_nick ()
GType | g_enum_register_static ()
GType | g_flags_register_static ()
void | g_enum_complete_type_info ()
void | g_flags_complete_type_info ()

## Types and Values

struct | GEnumClass
struct | GFlagsClass
struct | GEnumValue
struct | GFlagsValue

## Object Hierarchy

## Includes

    #include <glib-object.h>

## Description

The GLib type system provides fundamental types for enumeration and flags types. (Flags types are like enumerations, but allow their values to be combined by bitwise or). A registered enumeration or flags type associates a name and a nickname with each allowed value, and the methods `g_enum_get_value_by_name()`, `g_enum_get_value_by_nick()`, `g_flags_get_value_by_name()` and `g_flags_get_value_by_nick()` can look up values by their name or nickname. When an enumeration or flags type is registered with the GLib type system, it can be used as value type for object properties, using `g_param_spec_enum()` or `g_param_spec_flags()`.

GObject ships with a utility called glib-mkenums, that can construct suitable type registration functions from C enumeration definitions.

## Functions

### G_ENUM_CLASS_TYPE()

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

Get the type identifier from a given GEnumClass structure.

#### Parameters

class | a GEnumClass |

#### Returns

the GType

### G_ENUM_CLASS_TYPE_NAME()

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

Get the static type name from a given GEnumClass structure.

#### Parameters

class | a GEnumClass |

#### Returns

the type name.

### G_TYPE_IS_ENUM()

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

Checks whether `type` "is a" `G_TYPE_ENUM`.

#### Parameters

type | a GType ID. |

#### Returns

`TRUE` if `type` "is a" `G_TYPE_ENUM`.

### 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.

#### Parameters

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.

#### Parameters

class | a GEnumClass |

### G_TYPE_IS_FLAGS()

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

Checks whether `type` "is a" `G_TYPE_FLAGS`.

#### Parameters

type | a GType ID. |

#### Returns

`TRUE` if `type` "is a" `G_TYPE_FLAGS`.

### 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.

#### Parameters

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.

#### Parameters

class | a GFlagsClass |

### G_FLAGS_CLASS_TYPE()

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

Get the type identifier from a given GFlagsClass structure.

#### Parameters

class | a GFlagsClass |

#### Returns

the GType

### G_FLAGS_CLASS_TYPE_NAME()

    #define G_FLAGS_CLASS_TYPE_NAME(class) (g_type_name (G_FLAGS_CLASS_TYPE (class)))

Get the static type name from a given GFlagsClass structure.

#### Parameters

class | a GFlagsClass |

#### Returns

the type name.

### g_enum_get_value ()

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

Returns the GEnumValue for a value.

#### Parameters

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.

[transfer none]

### 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.

#### Parameters

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.

[transfer none]

### 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.

#### Parameters

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.

[transfer none]

### 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` .

#### Parameters

flags_class | a GFlagsClass |
value | the value |

#### Returns

the first GFlagsValue which is set in `value` , or `NULL` if none is set.

[transfer none]

### 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.

#### Parameters

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.

[transfer none]

### 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.

#### Parameters

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.

[transfer none]

### 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()`.

#### Parameters

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. GObject keeps a reference to the data, so it cannot be stack-allocated. |

#### 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()`.

#### Parameters

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. GObject keeps a reference to the data, so it cannot be stack-allocated. |

#### 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:

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    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);
    }

#### Parameters

g_enum_type | the type identifier of the type being completed |
info | the GTypeInfo struct to be filled in. | [out callee-allocates]
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_enum_complete_type_info()` above.

#### Parameters

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

## Types and Values

### struct GEnumClass

    struct GEnumClass {
      GTypeClass  g_type_class;

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

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

#### Members

GTypeClass `g_type_class`; | the parent 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. |

### struct GFlagsClass

    struct GFlagsClass {
      GTypeClass   g_type_class;

      guint	       mask;
      guint	       n_values;
      GFlagsValue *values;
    };

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

#### Members

GTypeClass `g_type_class`; | the parent 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. |

### struct GEnumValue

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

A structure which contains a single enum value, its name, and its nickname.

#### Members

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

### struct GFlagsValue

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

A structure which contains a single flags value, its name, and its nickname.

#### Members

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

## See Also

GParamSpecEnum, GParamSpecFlags, `g_param_spec_enum()`, `g_param_spec_flags()`