The delay between the device disappearing and the scan results being adjust is 
caused by caching in the Bluetooth stack. On Bluez the default is 2 or 3 mins 
for cache expiry. I have no data about other platforms. What platform are you 
on?


In fact in some cases the caching goes even further. Sometimes the details of 
the disappeared device are cached and when you connect you get data from the 
cache or the list of the services. This doesn't work on Bluez but I have seen 
this behavior on WinRT for example.


Unfortunately, there is not much you can do about it.

--

Alex


________________________________
From: Interest 
<interest-bounces+alexander.blasche=theqtcompany....@qt-project.org> on behalf 
of Dmytro Haponov <dmytro.hapo...@gmail.com>
Sent: Friday, February 19, 2016 13:16
To: interest@qt-project.org
Subject: [Interest] lowEnergyScanner detects ibeacons that are absent

after creating this topic
https://forum.qt.io/topic/64355/lowenergyscanner-example-shows-absent-devices/2
I was advised to address the question here.

The general question is - how to actively scan for BLE devices that are present 
at the moment of scan?

Dmytro Haponov
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