Document that QML_SINGLETON only works with QObjects

Change-Id: I18c38037cd635fa3300c761b16038b67ac3b0d74
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 03a2e51063de99f85b3b801c7ccd6663163a61b0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 8 insertions, 7 deletions

diff --git a/src/qml/doc/src/qmlfunctions.qdoc b/src/qml/doc/src/qmlfunctions.qdoc
index eb7983d077..c454d981a3 100644
--- a/src/qml/doc/src/qmlfunctions.qdoc
+++ b/src/qml/doc/src/qmlfunctions.qdoc
@@ -180,13 +180,14 @@
   \relates QQmlEngine
 
   Declares the enclosing type to be a singleton in QML. This only takes effect
-  if the type is available in QML, by having a \l QML_ELEMENT or
-  \l QML_NAMED_ELEMENT() macro. By default, each QQmlEngine will try to create a
-  singleton instance using either the type's default constructor or a static
-  factory function of the signature \c{T *create(QQmlEngine *, QJSEngine *)}
-  when the type is first accessed. If both do exist and are accessible, the
-  default constructor is preferred. If there is no default constructor and no
-  factory function the singleton is initially inaccessible.
+  if the type is a \l Q_OBJECT and is available in QML (by having a
+  \l QML_ELEMENT or \l QML_NAMED_ELEMENT() macro). By default, each QQmlEngine
+  will try to create a singleton instance using either the type's default
+  constructor or a static factory function of the signature
+  \c{T *create(QQmlEngine *, QJSEngine *)} when the type is first accessed.
+  If both do exist and are accessible, the default constructor is preferred.
+  If there is no default constructor and no factory function the singleton is
+  initially inaccessible.
 
   \sa QML_ELEMENT, QML_NAMED_ELEMENT(), qmlRegisterSingletonInstance().
 */