Add a warning when QBDDAgent::setLowEnergyDiscoveryTimeout is no-op

This can avoid accidental issues or wrong assumptions.

Task-number: QTBUG-53012
Change-Id: I02024a640f89954d6e55b87825276ea6f5f3d862
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent.cpp b/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
index b90f6b01..60af0e7e 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
@@ -40,9 +40,12 @@
 
 #include "qbluetoothdevicediscoveryagent.h"
 #include "qbluetoothdevicediscoveryagent_p.h"
+#include <QtCore/qloggingcategory.h>
 
 QT_BEGIN_NAMESPACE
 
+Q_DECLARE_LOGGING_CATEGORY(QT_BT)
+
 /*!
     \class QBluetoothDeviceDiscoveryAgent
     \inmodule QtBluetooth
@@ -253,8 +256,11 @@ void QBluetoothDeviceDiscoveryAgent::setLowEnergyDiscoveryTimeout(int timeout)
     Q_D(QBluetoothDeviceDiscoveryAgent);
 
     // cannot deliberately turn it off
-    if (d->lowEnergySearchTimeout < 0 || timeout < 0)
+    if (d->lowEnergySearchTimeout < 0 || timeout < 0) {
+        qCDebug(QT_BT) << "The Bluetooth Low Energy device discovery timeout cannot be negative "
+                          "or set on a backend which does not support this feature.";
         return;
+    }
 
     d->lowEnergySearchTimeout = timeout;
 }