1 files changed, 18 insertions, 3 deletions
diff --git a/src/Fl_Widget.cxx b/src/Fl_Widget.cxx
index 924cc3688..3982055b9 100644
--- a/src/Fl_Widget.cxx
+++ b/src/Fl_Widget.cxx
@@ -54,9 +54,24 @@ void Fl_Widget::default_callback(Fl_Widget *o, void * /*v*/) {
   }
 }
 /**
-    All Fl_Widgets that don't have a callback defined use a
-    default callback that puts a pointer to the widget in this queue,
-    and this method reads the oldest widget out of this queue.
+    Reads the default callback queue and returns the first widget.
+
+    All Fl_Widgets that don't have a callback defined use the default
+    callback \p static Fl_Widget::default_callback() that puts a pointer
+    to the widget in a queue. This method reads the oldest widget out
+    of this queue.
+
+    The queue (FIFO) is limited (currently 20 items). If the queue
+    overflows, the oldest entry (Fl_Widget *) is discarded.
+
+    Relying on the default callback and reading the callback queue with
+    Fl::readqueue() is not recommended. If you need a callback, you should
+    set one with Fl_Widget::callback(Fl_Callback *cb, void *data)
+    or one of its variants.
+
+    \see Fl_Widget::callback()
+    \see Fl_Widget::callback(Fl_Callback *cb, void *data)
+    \see Fl_Widget::default_callback()
 */
 Fl_Widget *Fl::readqueue() {
   if (obj_tail==obj_head) return 0;