undefined reference to QX11Info::display()

[watafaka]

Hi experts,
My project add these in Ubuntu 14 include <QtX11Extras/qx11info_x11.h> <X11/Xlib.h>,after build it occured "/usr/lib/i386-linux-gnu/libX11.so.6:-1: error: error adding symbols: DSO missing from command line".(libX11.so.6)
Then I add LIBS += -lX11 , i got these:
error: undefined reference to `QX11Info::display()'

error: undefined reference to `QX11Info::appRootWindow(int)'
error: collect2: error: ld returned 1 exit status
I can find the "libX11.so" in usr/lib/i386***/ ,anything wrong ? Help!

QT Version 5.3.2 on 32BIT

[andreyc]

What version of Qt do you use? Is it 32 or 64 bit build?
Take a look on this Question on SO