Doc: add a note that UniqueConnection does not work for lambdas

Task-number: QTBUG-52438
Change-Id: I3e4e5051937c40319d6efffd1491bef6feb6776e
Reviewed-by: Martin Smith <martin.smith@qt.io>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 63b02d2c0c..c44e4b16b1 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -2614,6 +2614,9 @@ static inline void check_and_warn_compat(const QMetaObject *sender, const QMetaM
     (exact same signal to the exact same slot on the same objects),
     the connection will fail and connect will return an invalid QMetaObject::Connection.
 
+    \note Qt::UniqueConnections do not work for lambdas, non-member functions
+    and functors; they only apply to connecting to member functions.
+
     The optional \a type parameter describes the type of connection
     to establish. In particular, it determines whether a particular
     signal is delivered to a slot immediately or queued for delivery
@@ -4665,7 +4668,10 @@ void qDeleteInEventHandler(QObject *o)
 
     Creates a connection of a given \a type from \a signal in
     \a sender object to \a functor to be placed in a specific event
-    loop of \a context, and returns a handle to the connection
+    loop of \a context, and returns a handle to the connection.
+
+    \note Qt::UniqueConnections do not work for lambdas, non-member functions
+    and functors; they only apply to connecting to member functions.
 
     The signal must be a function declared as a signal in the header.
     The slot function can be any function or functor that can be connected