Hello everyone,

I am developing a QML application that is to be used on raspberry pi. I also want to make file system read only so users can't mess something up and also I want to prolong micro SD card's life and prevent memory corruption in case of power loss.

When the application is started in writeble mode it works fine, but when I mount the file system as read only and try starting application i get the following error after about a second of running it(so the interface is shown and everything is working as supposed):
"QWidget: Cannot create a QWidgete without QApplication
Aborted"

I suppose that application tries to write something on file system and breaks when it fails. Can anyone help me by explaining how does it work under hood, and what must be kept writable so applications can work as supposed?

I found a alternative solution to mounting as read only, That is to use chattr command to force immunity on files(still don't know which ones exactly). But I am not sure can OS itself still access them when it needs to or not. As I said corruption during power loss is my greatest problem at the moment.

In addition I just want to say I am using Raspbian Jessie Lite, and Qt version is 5.6.0 if that means something to you.

Thanks in advance