* main (int argc,
* char *argv[])
* {
- * /* GValues must be initialized */
+ * // GValues must be initialized
* GValue a = G_VALUE_INIT;
* GValue b = G_VALUE_INIT;
* const gchar *message;
*
- * /* The GValue starts empty */
+ * // The GValue starts empty
* g_assert (!G_VALUE_HOLDS_STRING (&a));
*
- * /* Put a string in it */
+ * // Put a string in it
* g_value_init (&a, G_TYPE_STRING);
* g_assert (G_VALUE_HOLDS_STRING (&a));
* g_value_set_static_string (&a, "Hello, world!");
* g_printf ("%s\n", g_value_get_string (&a));
*
- * /* Reset it to its pristine state */
+ * // Reset it to its pristine state
* g_value_unset (&a);
*
- * /* It can then be reused for another type */
+ * // It can then be reused for another type
* g_value_init (&a, G_TYPE_INT);
* g_value_set_int (&a, 42);
*
- * /* Attempt to transform it into a GValue of type STRING */
+ * // Attempt to transform it into a GValue of type STRING
* g_value_init (&b, G_TYPE_STRING);
*
- * /* An INT is transformable to a STRING */
+ * // An INT is transformable to a STRING
* g_assert (g_value_type_transformable (G_TYPE_INT, G_TYPE_STRING));
*
* g_value_transform (&a, &b);
* g_printf ("%s\n", g_value_get_string (&b));
*
- * /* Attempt to transform it again using a custom transform function */
+ * // Attempt to transform it again using a custom transform function
* g_value_register_transform_func (G_TYPE_INT, G_TYPE_STRING, int2string);
* g_value_transform (&a, &b);
* g_printf ("%s\n", g_value_get_string (&b));
/**
* g_value_peek_pointer:
- * @value: An initialized #GValue structure.
+ * @value: An initialized #GValue structure
+ *
+ * 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.
*
- * Returns: (transfer none): 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.
+ * Returns: (transfer none): the value contents as pointer
*/
gpointer
g_value_peek_pointer (const GValue *value)
}
}
+/**
+ * g_value_init_from_instance:
+ * @value: An uninitialized #GValue structure.
+ * @instance: the instance
+ *
+ * Initializes and sets @value from an instantiatable type via the
+ * value_table's collect_value() function.
+ *
+ * Note: The @value will be initialised with the exact type of
+ * @instance. If you wish to set the @value's type to a different GType
+ * (such as a parent class GType), you need to manually call
+ * g_value_init() and g_value_set_instance().
+ *
+ * Since: 2.42
+ */
+void
+g_value_init_from_instance (GValue *value,
+ gpointer instance)
+{
+ g_return_if_fail (value != NULL && G_VALUE_TYPE(value) == 0);
+
+ if (G_IS_OBJECT (instance))
+ {
+ /* Fast-path.
+ * If G_IS_OBJECT() succeeds we know:
+ * * that instance is present and valid
+ * * that it is a GObject, and therefore we can directly
+ * use the collect implementation (g_object_ref) */
+ value_meminit (value, G_TYPE_FROM_INSTANCE (instance));
+ value->data[0].v_pointer = g_object_ref (instance);
+ }
+ else
+ {
+ GType g_type;
+ GTypeValueTable *value_table;
+ GTypeCValue cvalue;
+ gchar *error_msg;
+
+ g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
+
+ g_type = G_TYPE_FROM_INSTANCE (instance);
+ value_table = g_type_value_table_peek (g_type);
+ g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
+
+ memset (&cvalue, 0, sizeof (cvalue));
+ cvalue.v_pointer = instance;
+
+ /* setup and collect */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+ error_msg = value_table->collect_value (value, 1, &cvalue, 0);
+ if (error_msg)
+ {
+ g_warning ("%s: %s", G_STRLOC, error_msg);
+ g_free (error_msg);
+
+ /* we purposely leak the value here, it might not be
+ * in a sane state if an error condition occoured
+ */
+ value_meminit (value, g_type);
+ value_table->value_init (value);
+ }
+ }
+}
+
static GValueTransform
transform_func_lookup (GType src_type,
GType dest_type)