Clarify type transformability and comparability

If two GValues are transformable, it implies they are compatible,
so you do not need to check for compatibility yourself. Bump the
documentation to reflect this fact.

https://bugzilla.gnome.org/show_bug.cgi?id=707111

diff --git a/gobject/gvalue.c b/gobject/gvalue.c
index 280969e..ee40842 100644 (file)
--- a/gobject/gvalue.c
+++ b/gobject/gvalue.c
@@ -466,7 +466,9 @@ g_value_register_transform_func (GType           src_type,
  * @dest_type: Target type.
  *
  * Check whether g_value_transform() is able to transform values
- * of type @src_type into values of type @dest_type.
+ * of type @src_type into values of type @dest_type. Note that for
+ * the types to be transformable, they must be compatible and a
+ * transform function must be registered.
  *
  * Returns: %TRUE if the transformation is possible, %FALSE otherwise.
  */