"Unable to query physical screen size, defaulting to 100 dpi" error

[embdev]

Hi all,
I receive the following error when running my Qt 5 app. Is there a way to resolve this issue?

QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).

[mvuori]

I think this is a very common problem.
As this is the mobile & embedded forum, you might know the display and just set the variables as instructed.

[embdev]

@mvuori I see, but where may I set these variables in?

[jsulm]

@embdev In the console where you start the application.
Or you write a shell script which sets that variables and then starts your application.
Or you set those variables in the ~/.profile
Or you do it system wide in /etc/profile

[embdev]

@jsulm thanks for the advice! But do you know why how this error arise?