Build issues with libzbar based Qt application

Question

I am using libzbarQT (libzbarQT.so) in my QT code.I am facing an error while building the code saying "undefined reference to QWidget::qwsEvent(QWSEvent *event)".I am not using this function in my QT code.I want to know which function is internally calling this function so that I can tweak the library a bit. Any suggestions please..

Thanks in advance for any help.

PS: I am crosscompiling my code using arm-none-linux-gnueabi-g++ toolchain with LTIB. To solve error '/usr/lib/libzbarqt.so: undefined reference to QX11Info::display()', I have build Qt with X11.Now I am getting error:libzbarqt.so: undefined reference toQWidget::qwsEvent(QWSEvent*)' error.

Answer 1

In general, you could make sure that the symbols are present in the library unless it is built without symbols. I usually use the nm -a and objdump utilities for that operation.

More to the point: it seems that the zbar dynamic library that you have was built against the embedded version of Qt rather than the desktop Linux.

It is an unfortunate issue that both versions have the same dynamic library file names, so things like ldd cannot be much of help.

You will need to make sure to use exactly the same version of Qt installation that the library was built against. This means, if you use the desktop Linux installation for this, it will not work.