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Diffstat (limited to 'include/glib/gobject/gvalue.h')
| -rw-r--r-- | include/glib/gobject/gvalue.h | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/include/glib/gobject/gvalue.h b/include/glib/gobject/gvalue.h new file mode 100644 index 0000000000..9d8f03482a --- /dev/null +++ b/include/glib/gobject/gvalue.h @@ -0,0 +1,196 @@ +/* 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__ */ |