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/* GObject - GLib Type, Object, Parameter and Signal Library
* Copyright (C) 1997-1999, 2000-2001 Tim Janik and Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* gvalue.h: generic GValue functions
*/
#ifndef __G_VALUE_H__
#define __G_VALUE_H__
#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
#error "Only <glib-object.h> can be included directly."
#endif
#include <gobject/gtype.h>
G_BEGIN_DECLS
/* --- type macros --- */
/**
* G_TYPE_IS_VALUE:
* @type: A #GType value.
*
* Checks whether the passed in type ID can be used for g_value_init().
* That is, this macro checks whether this type provides an implementation
* of the #GTypeValueTable functions required for a type to create a #GValue of.
*
* Returns: Whether @type is suitable as a #GValue type.
*/
#define G_TYPE_IS_VALUE(type) (g_type_check_is_value_type (type))
/**
* G_IS_VALUE:
* @value: A #GValue structure.
*
* Checks if @value is a valid and initialized #GValue structure.
*
* Returns: %TRUE on success.
*/
#define G_IS_VALUE(value) (G_TYPE_CHECK_VALUE (value))
/**
* G_VALUE_TYPE:
* @value: A #GValue structure.
*
* Get the type identifier of @value.
*
* Returns: the #GType.
*/
#define G_VALUE_TYPE(value) (((GValue*) (value))->g_type)
/**
* G_VALUE_TYPE_NAME:
* @value: A #GValue structure.
*
* Gets the type name of @value.
*
* Returns: the type name.
*/
#define G_VALUE_TYPE_NAME(value) (g_type_name (G_VALUE_TYPE (value)))
/**
* G_VALUE_HOLDS:
* @value: A #GValue structure.
* @type: A #GType value.
*
* Checks if @value holds (or contains) a value of @type.
* This macro will also check for @value != %NULL and issue a
* warning if the check fails.
*
* Returns: %TRUE if @value holds the @type.
*/
#define G_VALUE_HOLDS(value,type) (G_TYPE_CHECK_VALUE_TYPE ((value), (type)))
/* --- typedefs & structures --- */
/**
* GValueTransform:
* @src_value: Source value.
* @dest_value: Target value.
*
* The type of value transformation functions which can be registered with
* g_value_register_transform_func().
*
* @dest_value will be initialized to the correct destination type.
*/
typedef void (*GValueTransform) (const GValue *src_value,
GValue *dest_value);
/**
* GValue:
*
* 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.
*/
struct _GValue
{
/*< private >*/
GType g_type;
/* public for GTypeValueTable methods */
union {
gint v_int;
guint v_uint;
glong v_long;
gulong v_ulong;
gint64 v_int64;
guint64 v_uint64;
gfloat v_float;
gdouble v_double;
gpointer v_pointer;
} data[2];
};
/* --- prototypes --- */
GLIB_AVAILABLE_IN_ALL
GValue* g_value_init (GValue *value,
GType g_type);
GLIB_AVAILABLE_IN_ALL
void g_value_copy (const GValue *src_value,
GValue *dest_value);
GLIB_AVAILABLE_IN_ALL
GValue* g_value_reset (GValue *value);
GLIB_AVAILABLE_IN_ALL
void g_value_unset (GValue *value);
GLIB_AVAILABLE_IN_ALL
void g_value_set_instance (GValue *value,
gpointer instance);
GLIB_AVAILABLE_IN_2_42
void g_value_init_from_instance (GValue *value,
gpointer instance);
/* --- private --- */
GLIB_AVAILABLE_IN_ALL
gboolean g_value_fits_pointer (const GValue *value);
GLIB_AVAILABLE_IN_ALL
gpointer g_value_peek_pointer (const GValue *value);
/* --- implementation details --- */
GLIB_AVAILABLE_IN_ALL
gboolean g_value_type_compatible (GType src_type,
GType dest_type);
GLIB_AVAILABLE_IN_ALL
gboolean g_value_type_transformable (GType src_type,
GType dest_type);
GLIB_AVAILABLE_IN_ALL
gboolean g_value_transform (const GValue *src_value,
GValue *dest_value);
GLIB_AVAILABLE_IN_ALL
void g_value_register_transform_func (GType src_type,
GType dest_type,
GValueTransform transform_func);
/**
* G_VALUE_NOCOPY_CONTENTS:
*
* If passed to G_VALUE_COLLECT(), allocated data won't be copied
* but used verbatim. This does not affect ref-counted types like
* objects.
*/
#define G_VALUE_NOCOPY_CONTENTS (1 << 27)
/**
* G_VALUE_INIT:
*
* A #GValue must be initialized before it can be used. This macro can
* be used as initializer instead of an explicit `{ 0 }` when declaring
* a variable, but it cannot be assigned to a variable.
*
* |[
* GValue value = G_VALUE_INIT;
* ]|
*
* Since: 2.30
*/
#define G_VALUE_INIT { 0, { { 0 } } }
G_END_DECLS
#endif /* __G_VALUE_H__ */
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