1 /* GObject - GLib Type, Object, Parameter and Signal Library 2 * Copyright (C) 1997-1999, 2000-2001 Tim Janik and Red Hat, Inc. 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation; either 7 * version 2 of the License, or (at your option) any later version. 8 * 9 * This library is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Lesser General Public License for more details. 13 * 14 * You should have received a copy of the GNU Lesser General 15 * Public License along with this library; if not, write to the 16 * Free Software Foundation, Inc., 59 Temple Place, Suite 330, 17 * Boston, MA 02111-1307, USA. 18 * 19 * gvalue.h: generic GValue functions 20 */ 21 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION) 22 #error "Only <glib-object.h> can be included directly." 23 #endif 24 25 #ifndef __G_VALUE_H__ 26 #define __G_VALUE_H__ 27 28 #include <gobject/gtype.h> 29 30 G_BEGIN_DECLS 31 32 /* --- type macros --- */ 33 /** 34 * G_TYPE_IS_VALUE: 35 * @type: A #GType value. 36 * 37 * Checks whether the passed in type ID can be used for g_value_init(). 38 * That is, this macro checks whether this type provides an implementation 39 * of the #GTypeValueTable functions required for a type to create a #GValue of. 40 * 41 * Returns: Whether @type is suitable as a #GValue type. 42 */ 43 #define G_TYPE_IS_VALUE(type) (g_type_check_is_value_type (type)) 44 /** 45 * G_IS_VALUE: 46 * @value: A #GValue structure. 47 * 48 * Checks if @value is a valid and initialized #GValue structure. 49 * 50 * Returns: %TRUE on success. 51 */ 52 #define G_IS_VALUE(value) (G_TYPE_CHECK_VALUE (value)) 53 /** 54 * G_VALUE_TYPE: 55 * @value: A #GValue structure. 56 * 57 * Get the type identifier of @value. 58 * 59 * Returns: the #GType. 60 */ 61 #define G_VALUE_TYPE(value) (((GValue*) (value))->g_type) 62 /** 63 * G_VALUE_TYPE_NAME: 64 * @value: A #GValue structure. 65 * 66 * Gets the the type name of @value. 67 * 68 * Returns: the type name. 69 */ 70 #define G_VALUE_TYPE_NAME(value) (g_type_name (G_VALUE_TYPE (value))) 71 /** 72 * G_VALUE_HOLDS: 73 * @value: A #GValue structure. 74 * @type: A #GType value. 75 * 76 * Checks if @value holds (or contains) a value of @type. 77 * This macro will also check for @value != %NULL and issue a 78 * warning if the check fails. 79 * 80 * Returns: %TRUE if @value holds the @type. 81 */ 82 #define G_VALUE_HOLDS(value,type) (G_TYPE_CHECK_VALUE_TYPE ((value), (type))) 83 84 85 /* --- typedefs & structures --- */ 86 /** 87 * GValueTransform: 88 * @src_value: Source value. 89 * @dest_value: Target value. 90 * 91 * The type of value transformation functions which can be registered with 92 * g_value_register_transform_func(). 93 */ 94 typedef void (*GValueTransform) (const GValue *src_value, 95 GValue *dest_value); 96 /** 97 * GValue: 98 * 99 * An opaque structure used to hold different types of values. 100 * The data within the structure has protected scope: it is accessible only 101 * to functions within a #GTypeValueTable structure, or implementations of 102 * the g_value_*() API. That is, code portions which implement new fundamental 103 * types. 104 * #GValue users can not make any assumptions about how data is stored 105 * within the 2 element @data union, and the @g_type member should 106 * only be accessed through the G_VALUE_TYPE() macro. 107 */ 108 struct _GValue 109 { 110 /*< private >*/ 111 GType g_type; 112 113 /* public for GTypeValueTable methods */ 114 union { 115 gint v_int; 116 guint v_uint; 117 glong v_long; 118 gulong v_ulong; 119 gint64 v_int64; 120 guint64 v_uint64; 121 gfloat v_float; 122 gdouble v_double; 123 gpointer v_pointer; 124 } data[2]; 125 }; 126 127 128 /* --- prototypes --- */ 129 GValue* g_value_init (GValue *value, 130 GType g_type); 131 void g_value_copy (const GValue *src_value, 132 GValue *dest_value); 133 GValue* g_value_reset (GValue *value); 134 void g_value_unset (GValue *value); 135 void g_value_set_instance (GValue *value, 136 gpointer instance); 137 138 139 /* --- private --- */ 140 gboolean g_value_fits_pointer (const GValue *value); 141 gpointer g_value_peek_pointer (const GValue *value); 142 143 144 /* --- implementation details --- */ 145 gboolean g_value_type_compatible (GType src_type, 146 GType dest_type); 147 gboolean g_value_type_transformable (GType src_type, 148 GType dest_type); 149 gboolean g_value_transform (const GValue *src_value, 150 GValue *dest_value); 151 void g_value_register_transform_func (GType src_type, 152 GType dest_type, 153 GValueTransform transform_func); 154 #define G_VALUE_NOCOPY_CONTENTS (1 << 27) 155 156 157 G_END_DECLS 158 159 #endif /* __G_VALUE_H__ */ 160