Struct

GObjectValue

Description [src]

struct GValue {
  None data;
}

An opaque structure used to hold different types of values.

The data within the structure has protected scope: it is accessible only to functions within a GTypeValueTable structure, or implementations of the g_value_*() API. That is, code portions which implement new fundamental types.

GValue users cannot make any assumptions about how data is stored within the 2 element data union, and the g_type member should only be accessed through the G_VALUE_TYPE() macro.

Structure members
data No description available.

Functions

g_value_register_transform_func

Registers a value transformation function for use in g_value_transform(). A previously registered transformation function for src_type and dest_type will be replaced.

g_value_type_compatible

Returns whether a GValue of type src_type can be copied into a GValue of type dest_type.

g_value_type_transformable

Check whether g_value_transform() is able to transform values of type src_type into values of type dest_type. Note that for the types to be transformable, they must be compatible or a transformation function must be registered.

Instance methods

g_value_copy

Copies the value of src_value into dest_value.

g_value_dup_boxed

Get the contents of a G_TYPE_BOXED derived GValue. Upon getting, the boxed value is duplicated and needs to be later freed with g_boxed_free(), e.g. like: g_boxed_free (G_VALUE_TYPE (value), return_value);

g_value_dup_object

Get the contents of a G_TYPE_OBJECT derived GValue, increasing its reference count. If the contents of the GValue are NULL, then NULL will be returned.

g_value_dup_param

Get the contents of a G_TYPE_PARAM GValue, increasing its reference count.

g_value_dup_string

Get a copy the contents of a G_TYPE_STRING GValue.

g_value_dup_variant

Get the contents of a variant GValue, increasing its refcount. The returned GVariant is never floating.

Available since: 2.26

g_value_fits_pointer

Determines if value will fit inside the size of a pointer value. This is an internal function introduced mainly for C marshallers.

g_value_get_boolean

Get the contents of a G_TYPE_BOOLEAN GValue.

g_value_get_boxed

Get the contents of a G_TYPE_BOXED derived GValue.

g_value_get_char

Do not use this function; it is broken on platforms where the %char type is unsigned, such as ARM and PowerPC. See g_value_get_schar().

Deprecated since: 2.32

g_value_get_double

Get the contents of a G_TYPE_DOUBLE GValue.

g_value_get_enum

Get the contents of a G_TYPE_ENUM GValue.

g_value_get_flags

Get the contents of a G_TYPE_FLAGS GValue.

g_value_get_float

Get the contents of a G_TYPE_FLOAT GValue.

g_value_get_gtype

Get the contents of a G_TYPE_GTYPE GValue.

Available since: 2.12

g_value_get_int

Get the contents of a G_TYPE_INT GValue.

g_value_get_int64

Get the contents of a G_TYPE_INT64 GValue.

g_value_get_long

Get the contents of a G_TYPE_LONG GValue.

g_value_get_object

Get the contents of a G_TYPE_OBJECT derived GValue.

g_value_get_param

Get the contents of a G_TYPE_PARAM GValue.

g_value_get_pointer

Get the contents of a pointer GValue.

g_value_get_schar

Get the contents of a G_TYPE_CHAR GValue.

Available since: 2.32

g_value_get_string

Get the contents of a G_TYPE_STRING GValue.

g_value_get_uchar

Get the contents of a G_TYPE_UCHAR GValue.

g_value_get_uint

Get the contents of a G_TYPE_UINT GValue.

g_value_get_uint64

Get the contents of a G_TYPE_UINT64 GValue.

g_value_get_ulong

Get the contents of a G_TYPE_ULONG GValue.

g_value_get_variant

Get the contents of a variant GValue.

Available since: 2.26

g_value_init

Initializes value with the default value of type.

g_value_init_from_instance

Initializes and sets value from an instantiatable type via the value_table’s collect_value() function.

Available since: 2.42

g_value_peek_pointer

Returns the value contents as pointer. This function asserts that g_value_fits_pointer() returned TRUE for the passed in value. This is an internal function introduced mainly for C marshallers.

g_value_reset

Clears the current value in value and resets it to the default value (as if the value had just been initialized).

g_value_set_boolean

Set the contents of a G_TYPE_BOOLEAN GValue to v_boolean.

g_value_set_boxed

Set the contents of a G_TYPE_BOXED derived GValue to v_boxed.

g_value_set_boxed_take_ownership

This is an internal function introduced mainly for C marshallers.

Deprecated since: 2.4

g_value_set_char

Set the contents of a G_TYPE_CHAR GValue to v_char.

Deprecated since: 2.32

g_value_set_double

Set the contents of a G_TYPE_DOUBLE GValue to v_double.

g_value_set_enum

Set the contents of a G_TYPE_ENUM GValue to v_enum.

g_value_set_flags

Set the contents of a G_TYPE_FLAGS GValue to v_flags.

g_value_set_float

Set the contents of a G_TYPE_FLOAT GValue to v_float.

g_value_set_gtype

Set the contents of a G_TYPE_GTYPE GValue to v_gtype.

Available since: 2.12

g_value_set_instance

Sets value from an instantiatable type via the value_table’s collect_value() function.

g_value_set_int

Set the contents of a G_TYPE_INT GValue to v_int.

g_value_set_int64

Set the contents of a G_TYPE_INT64 GValue to v_int64.

g_value_set_interned_string

Set the contents of a G_TYPE_STRING GValue to v_string. The string is assumed to be static and interned (canonical, for example from g_intern_string()), and is thus not duplicated when setting the GValue.

Available since: 2.66

g_value_set_long

Set the contents of a G_TYPE_LONG GValue to v_long.

g_value_set_object

Set the contents of a G_TYPE_OBJECT derived GValue to v_object.

g_value_set_object_take_ownership

This is an internal function introduced mainly for C marshallers.

Deprecated since: 2.4

g_value_set_param

Set the contents of a G_TYPE_PARAM GValue to param.

g_value_set_param_take_ownership

This is an internal function introduced mainly for C marshallers.

Deprecated since: 2.4

g_value_set_pointer

Set the contents of a pointer GValue to v_pointer.

g_value_set_schar

Set the contents of a G_TYPE_CHAR GValue to v_char.

Available since: 2.32

g_value_set_static_boxed

Set the contents of a G_TYPE_BOXED derived GValue to v_boxed.

g_value_set_static_string

Set the contents of a G_TYPE_STRING GValue to v_string. The string is assumed to be static, and is thus not duplicated when setting the GValue.

g_value_set_string

Set the contents of a G_TYPE_STRING GValue to a copy of v_string.

g_value_set_string_take_ownership

This is an internal function introduced mainly for C marshallers.

Deprecated since: 2.4

g_value_set_uchar

Set the contents of a G_TYPE_UCHAR GValue to v_uchar.

g_value_set_uint

Set the contents of a G_TYPE_UINT GValue to v_uint.

g_value_set_uint64

Set the contents of a G_TYPE_UINT64 GValue to v_uint64.

g_value_set_ulong

Set the contents of a G_TYPE_ULONG GValue to v_ulong.

g_value_set_variant

Set the contents of a variant GValue to variant. If the variant is floating, it is consumed.

Available since: 2.26

g_value_take_boxed

Sets the contents of a G_TYPE_BOXED derived GValue to v_boxed and takes over the ownership of the caller’s reference to v_boxed; the caller doesn’t have to unref it any more.

Available since: 2.4

g_value_take_object

Sets the contents of a G_TYPE_OBJECT derived GValue to v_object and takes over the ownership of the caller’s reference to v_object; the caller doesn’t have to unref it any more (i.e. the reference count of the object is not increased).

Available since: 2.4

g_value_take_param

Sets the contents of a G_TYPE_PARAM GValue to param and takes over the ownership of the caller’s reference to param; the caller doesn’t have to unref it any more.

Available since: 2.4

g_value_take_string

Sets the contents of a G_TYPE_STRING GValue to v_string.

Available since: 2.4

g_value_take_variant

Set the contents of a variant GValue to variant, and takes over the ownership of the caller’s reference to variant; the caller doesn’t have to unref it any more (i.e. the reference count of the variant is not increased).

Available since: 2.26

g_value_transform

Tries to cast the contents of src_value into a type appropriate to store in dest_value, e.g. to transform a G_TYPE_INT value into a G_TYPE_FLOAT value. Performing transformations between value types might incur precision lossage. Especially transformations into strings might reveal seemingly arbitrary results and shouldn’t be relied upon for production code (such as rcfile value or object property serialization).

g_value_unset

Clears the current value in value (if any) and “unsets” the type, this releases all resources associated with this GValue. An unset value is the same as an uninitialized (zero-filled) GValue structure.