Qt Embedded 4.8.5 cannot open display lock

qtsri · wrote on 17 Jun 2021, 02:06

We are running a Qt Embedded 4.8.5 application on Android 9 OSP and seeing this error:

QLock::QLock: Cannot create semaphore /tmp/qtembedded-0/QtEmbedded-0 'd' (38, Function not implemented)
Cannot get display lock
Aborted

despite enabling SYSVIPC in the underlying Linux kernel.

SGaist · wrote on 17 Jun 2021, 07:45

Hi,

Did you implement the code as well in Qt ?
By the way, if your are locked to Qt 4, at least consider using the latest version of that series.

qtsri · wrote on 17 Jun 2021, 11:37

Hi.
Yes, the code is implemented using Qt 4.8.5. We can try with 4.8.7. Thanks.

qtsri · wrote on 17 Jun 2021, 19:50

We didn't have to upgrade to Qt 4.8.7 as were using the Android 9 kernel that doesn't use System V IPC where we assumed we were using Linux kernel with system V enabled. Pointing to the correct kernel in the build fixed the issue.

SGaist · wrote on 17 Jun 2021, 20:01

Nice !

Note that the upgrade is still a good idea since you are using an outdated version of Qt. Even more, it has reached end of life a long time ago.