Doc: Added information about the Qt::AutoCompatConnection enum value.

Task-number: 235850
Reviewed-by: Trust Me

2 files changed, 21 insertions, 1 deletions

diff --git a/doc/src/classes/qnamespace.qdoc b/doc/src/classes/qnamespace.qdoc
index a49e079be3..18ecd7bbec 100644
--- a/doc/src/classes/qnamespace.qdoc
+++ b/doc/src/classes/qnamespace.qdoc
@@ -514,7 +514,6 @@
     slots. In particular, it determines whether a particular signal is delivered to a
     slot immediately or queued for delivery at a later time.
 
-    \omitvalue AutoCompatConnection
     \value DirectConnection  When emitted, the signal is immediately delivered to the slot.
     \value QueuedConnection  When emitted, the signal is queued until the event loop is
                              able to deliver it to the slot.
@@ -533,6 +532,12 @@
                              not already connected to the same slot before connecting, otherwise,
                              the connection will fail.
                              This value was introduced in Qt 4.6.
+    \value AutoCompatConnection
+           The default connection type for signals and slots when Qt 3 support
+           is enabled. Equivalent to AutoConnection for connections but will cause warnings
+           to be output under certain circumstances. See
+           \l{Porting to Qt 4#Compatibility Signals and Slots}{Compatibility Signals and Slots}
+           for further information.
 
     With queued connections, the parameters must be of types that are known to
     Qt's meta-object system, because Qt needs to copy the arguments to store them
diff --git a/doc/src/porting4.qdoc b/doc/src/porting4.qdoc
index 963b918238..286e10d024 100644
--- a/doc/src/porting4.qdoc
+++ b/doc/src/porting4.qdoc
@@ -561,6 +561,21 @@
     \note Setting widget attributes to disable key features of Qt's widget
     rendering model may also cause other features to be disabled.
 
+    \section1 Compatibility Signals and Slots
+
+    When \c QT3_SUPPORT is defined, the default connection type for signals
+    and slots is the Qt::AutoCompatConnection type. This allows so-called
+    \e compatibility signals and slots (defined in Qt 3 support mode to provide
+    Qt 3 compatibility features) to be connected to other signals and
+    slots.
+
+    However, if Qt is compiled with debugging output enabled, and the
+    developer uses other connection types to connect to compatibility
+    signals and slots (perhaps by building their application without Qt 3
+    support enabled), then Qt will output warnings to the console to
+    indicate that compatibility connections are being made. This is intended
+    to be used as an aid in the process of porting a Qt 3 application to Qt 4.
+
     \section1 QAccel
 
     The \c QAccel class has been renamed Q3Accel and moved to the