[Error] undefined symbol: _ZN7QWidget8qwsEventEP8QWSEvent

rocket42

I created C++ class manually, this class calls abc and inherited from QMainWindow class
source code of abc.h:

#ifndef ABC_H
#define ABC_H
#include <QMainWindow>
class abc : public QMainWindow
{
    Q_OBJECT
public:
    explicit abc(QWidget *parent = 0);
signals:
public slots:
};
#endif // ABC_H

source code of abc.cpp:

#include "abc.h"
abc::abc(QWidget *parent) : QMainWindow(parent)
{

}

source of main.cpp:

#include "mainwindow.h"
#include <QApplication>
#include "abc.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
//    MainWindow w;
//    w.show();
//    QMainWindow q;
//    q.show();
    abc abc1;
    abc1.show();
    return a.exec();
}

when app run on beagbone black, this error still rises

SGaist

There's something illogical here so lets try to summaries things:
First case:

You create a default widget project with Qt Creator
Replace the MainWindow call in main.cpp by a QMainWindow
Build it with your cross-compiled Qt
Runs on BBB

Second case:

You create a default widget project with Qt Creator
You keep the MainWindow class
Build it with your cross-compiled Qt
Fails to run on BBB complaining about QWS

In both case, you use the exact same version of Qt to build (i.e. cross-compile) the projects.

Is the summary correct ?

rocket42

yes, you are right. but you miss the third case.
because i have three cases.
the third case:

I create a default widget project with Qt Creator
I create a new class (name is ABC) which inherite from QMainWindow (source code I posted at #21)
Replace the MainWindow class in main.cpp by ABC class
Build it with your cross-compiled Qt
Fails to run on BBB complaining about QWS
All of three cases, i use same KIT (included device, compiler, qmake,...)

SGaist

I must say that it defies logic...

rocket42

sorry, i don't understand
all three cases is different.
the third case i don't use class which automatically create by Qt creator, i created manually

SGaist

That's why it defies logic. I don't see why a simple derived class would trigger that error.

Can you run ldd on all three applications on your target and post the output ?

rocket42

output of case1 (application run ok):
libQtGui.so.4 => /usr/lib/arm-linux-gnueabihf/libQtGui.so.4 (0xb681e000)
libQtCore.so.4 => /usr/lib/arm-linux-gnueabihf/libQtCore.so.4 (0xb6616000)
libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0xb656b000)
libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0xb6547000)
libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6462000)
libfontconfig.so.1 => /usr/lib/arm-linux-gnueabihf/libfontconfig.so.1 (0xb6436000)
libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0xb641a000)
libaudio.so.2 => /usr/lib/arm-linux-gnueabihf/libaudio.so.2 (0xb6402000)
libglib-2.0.so.0 => /lib/arm-linux-gnueabihf/libglib-2.0.so.0 (0xb6343000)
libpng12.so.0 => /lib/arm-linux-gnueabihf/libpng12.so.0 (0xb6322000)
libz.so.1 => /lib/arm-linux-gnueabihf/libz.so.1 (0xb6309000)
libfreetype.so.6 => /usr/lib/arm-linux-gnueabihf/libfreetype.so.6 (0xb62a4000)
libgobject-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgobject-2.0.so.0 (0xb6265000)
libSM.so.6 => /usr/lib/arm-linux-gnueabihf/libSM.so.6 (0xb6258000)
libICE.so.6 => /usr/lib/arm-linux-gnueabihf/libICE.so.6 (0xb6240000)
libXrender.so.1 => /usr/lib/arm-linux-gnueabihf/libXrender.so.1 (0xb6232000)
libXext.so.6 => /usr/lib/arm-linux-gnueabihf/libXext.so.6 (0xb621f000)
libX11.so.6 => /usr/lib/arm-linux-gnueabihf/libX11.so.6 (0xb6136000)
libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0xb60cb000)
/lib/ld-linux-armhf.so.3 (0xb6f02000)
libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb60c0000)
librt.so.1 => /lib/arm-linux-gnueabihf/librt.so.1 (0xb60b2000)
libexpat.so.1 => /lib/arm-linux-gnueabihf/libexpat.so.1 (0xb6090000)
libXt.so.6 => /usr/lib/arm-linux-gnueabihf/libXt.so.6 (0xb604e000)
libXau.so.6 => /usr/lib/arm-linux-gnueabihf/libXau.so.6 (0xb6044000)
libpcre.so.3 => /lib/arm-linux-gnueabihf/libpcre.so.3 (0xb600b000)
libgthread-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgthread-2.0.so.0 (0xb6001000)
libffi.so.5 => /usr/lib/arm-linux-gnueabihf/libffi.so.5 (0xb5fef000)
libuuid.so.1 => /lib/arm-linux-gnueabihf/libuuid.so.1 (0xb5fe3000)
libxcb.so.1 => /usr/lib/arm-linux-gnueabihf/libxcb.so.1 (0xb5fc8000)
libXdmcp.so.6 => /usr/lib/arm-linux-gnueabihf/libXdmcp.so.6 (0xb5fbd000)
output of case2 ( keep the MainWindow class):
libQtGui.so.4 => /usr/lib/arm-linux-gnueabihf/libQtGui.so.4 (0xb68fd000)
libQtCore.so.4 => /usr/lib/arm-linux-gnueabihf/libQtCore.so.4 (0xb66f5000)
libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0xb664a000)
libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0xb6626000)
libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6541000)
libfontconfig.so.1 => /usr/lib/arm-linux-gnueabihf/libfontconfig.so.1 (0xb6515000)
libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0xb64f9000)
libaudio.so.2 => /usr/lib/arm-linux-gnueabihf/libaudio.so.2 (0xb64e1000)
libglib-2.0.so.0 => /lib/arm-linux-gnueabihf/libglib-2.0.so.0 (0xb6422000)
libpng12.so.0 => /lib/arm-linux-gnueabihf/libpng12.so.0 (0xb6401000)
libz.so.1 => /lib/arm-linux-gnueabihf/libz.so.1 (0xb63e8000)
libfreetype.so.6 => /usr/lib/arm-linux-gnueabihf/libfreetype.so.6 (0xb6383000)
libgobject-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgobject-2.0.so.0 (0xb6344000)
libSM.so.6 => /usr/lib/arm-linux-gnueabihf/libSM.so.6 (0xb6337000)
libICE.so.6 => /usr/lib/arm-linux-gnueabihf/libICE.so.6 (0xb631f000)
libXrender.so.1 => /usr/lib/arm-linux-gnueabihf/libXrender.so.1 (0xb6311000)
libXext.so.6 => /usr/lib/arm-linux-gnueabihf/libXext.so.6 (0xb62fe000)
libX11.so.6 => /usr/lib/arm-linux-gnueabihf/libX11.so.6 (0xb6215000)
libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0xb61aa000)
/lib/ld-linux-armhf.so.3 (0xb6fe1000)
libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb619f000)
librt.so.1 => /lib/arm-linux-gnueabihf/librt.so.1 (0xb6191000)
libexpat.so.1 => /lib/arm-linux-gnueabihf/libexpat.so.1 (0xb616f000)
libXt.so.6 => /usr/lib/arm-linux-gnueabihf/libXt.so.6 (0xb612d000)
libXau.so.6 => /usr/lib/arm-linux-gnueabihf/libXau.so.6 (0xb6123000)
libpcre.so.3 => /lib/arm-linux-gnueabihf/libpcre.so.3 (0xb60ea000)
libgthread-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgthread-2.0.so.0 (0xb60e0000)
libffi.so.5 => /usr/lib/arm-linux-gnueabihf/libffi.so.5 (0xb60ce000)
libuuid.so.1 => /lib/arm-linux-gnueabihf/libuuid.so.1 (0xb60c2000)
libxcb.so.1 => /usr/lib/arm-linux-gnueabihf/libxcb.so.1 (0xb60a7000)
libXdmcp.so.6 => /usr/lib/arm-linux-gnueabihf/libXdmcp.so.6 (0xb609c000)
output of case3 (use abc class):
libQtGui.so.4 => /usr/lib/arm-linux-gnueabihf/libQtGui.so.4 (0xb681c000)
libQtCore.so.4 => /usr/lib/arm-linux-gnueabihf/libQtCore.so.4 (0xb6614000)
libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0xb6569000)
libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0xb6545000)
libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6460000)
libfontconfig.so.1 => /usr/lib/arm-linux-gnueabihf/libfontconfig.so.1 (0xb6434000)
libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0xb6418000)
libaudio.so.2 => /usr/lib/arm-linux-gnueabihf/libaudio.so.2 (0xb6400000)
libglib-2.0.so.0 => /lib/arm-linux-gnueabihf/libglib-2.0.so.0 (0xb6341000)
libpng12.so.0 => /lib/arm-linux-gnueabihf/libpng12.so.0 (0xb6320000)
libz.so.1 => /lib/arm-linux-gnueabihf/libz.so.1 (0xb6307000)
libfreetype.so.6 => /usr/lib/arm-linux-gnueabihf/libfreetype.so.6 (0xb62a2000)
libgobject-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgobject-2.0.so.0 (0xb6263000)
libSM.so.6 => /usr/lib/arm-linux-gnueabihf/libSM.so.6 (0xb6256000)
libICE.so.6 => /usr/lib/arm-linux-gnueabihf/libICE.so.6 (0xb623e000)
libXrender.so.1 => /usr/lib/arm-linux-gnueabihf/libXrender.so.1 (0xb6230000)
libXext.so.6 => /usr/lib/arm-linux-gnueabihf/libXext.so.6 (0xb621d000)
libX11.so.6 => /usr/lib/arm-linux-gnueabihf/libX11.so.6 (0xb6134000)
libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0xb60c9000)
/lib/ld-linux-armhf.so.3 (0xb6f00000)
libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb60be000)
librt.so.1 => /lib/arm-linux-gnueabihf/librt.so.1 (0xb60b0000)
libexpat.so.1 => /lib/arm-linux-gnueabihf/libexpat.so.1 (0xb608e000)
libXt.so.6 => /usr/lib/arm-linux-gnueabihf/libXt.so.6 (0xb604c000)
libXau.so.6 => /usr/lib/arm-linux-gnueabihf/libXau.so.6 (0xb6042000)
libpcre.so.3 => /lib/arm-linux-gnueabihf/libpcre.so.3 (0xb6009000)
libgthread-2.0.so.0 => /usr/lib/arm-linux-gnueabihf/libgthread-2.0.so.0 (0xb5fff000)
libffi.so.5 => /usr/lib/arm-linux-gnueabihf/libffi.so.5 (0xb5fed000)
libuuid.so.1 => /lib/arm-linux-gnueabihf/libuuid.so.1 (0xb5fe1000)
libxcb.so.1 => /usr/lib/arm-linux-gnueabihf/libxcb.so.1 (0xb5fc6000)
libXdmcp.so.6 => /usr/lib/arm-linux-gnueabihf/libXdmcp.so.6 (0xb5fbb000)

SGaist

So there's indeed something funky going on. On your target you have your application loading the "desktop Qt 4" while you are cross-compiling on your machine.

So again, if you are using your application with QWS on the target, install your cross-compiled Qt on it. If not, cross-compile Qt 4 again but not for embedded.

rocket42

output ldd of case 1 and case 2 is same.
case 1 is ok. but, case 2 is not ok. why?

SGaist

Like I said, from your description that's pretty mysterious. Did you try to run them with your cross-compiled Qt installed on the target ?

rocket42

please go to this site:
http://exploringbeaglebone.com/chapter11/#Step_2_Installing_Qt_48x
i follow it.