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Edit File: gvalue.h

/* 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. This does not affect usage of g_value_copy(), the data will * be copied if it is not ref-counted. */ #define G_VALUE_NOCOPY_CONTENTS (1 << 27) /** * G_VALUE_INTERNED_STRING: * * For string values, indicates that the string contained is canonical and will * exist for the duration of the process. See g_value_set_interned_string(). * * Since: 2.66 */ #define G_VALUE_INTERNED_STRING (1 << 28) GLIB_AVAILABLE_MACRO_IN_2_66 /** * 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__ */