[Qt-creator] QFile read blocks forever on stty USB unplugging

[Christophe Meessen]

Hello,

my program has to communicate with a device through an RS232 connection. 
My OS is Linux and I'm using a USB to RS232 cable.

I'm also using the qextserialport library but I suspect the problem is 
in QFile read operation.

I'm not testing robustness of the system by checking how my program 
behaves when the device is switched off and on.

The thing is that I open a device file to communicate with RS232. The 
connection remains open and functionning when the device is switched off 
and on. The read operation timesout and I can detect this since I get an 
empty response back. Retrying periodically is all it takes to recover 
when the device is switched on again.

The problem shows up when I unplug the usb cable from the PC. The read 
operation seem to block forever (I didn't wait more than 10s though). If 
I reconnect the usb, it is assigned a different device file name and the 
program remains blocked. I have to kill it to stop it. The blocking read 
is in a separate thread for asynchronous operation.

Shouldn't there be a timeout or a detection of the usb plug disconnection ?