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Old 01-14-2005, 07:24 AM   #1
jordban
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Compile QT get Undefined reference


Hello,
I got finally QT installed and im working on a test copmile to make sure everything is working.
First i have a main.cpp which contains
Code:
#include <qapplication.h>
#include <qpushbutton.h>

int main( int argc, char **argv )
{
    QApplication a( argc, argv );

    QPushButton hello( "Hello world!", 0 );
    hello.resize( 100, 30 );

    a.setMainWidget( &hello );
    hello.show();
    return a.exec();
}
Next i type in qmake -project to build a .pro project file, then i trype in qmake to make a makefile. Finally i type in make to compile the project but i get back these errors
Code:
g++ -c -pipe -Wall -W -O2 -DQT_NO_DEBUG  -I/home/jordan/qt3/mkspecs/linux-g++ -I. -I. -I/home/jordan/qt3/include -o main.o main.cpp
g++  -o qt main.o    -L/usr/X11R6/lib -lXext -lX11 -lm
main.o(.text+0x1e): In function `main':
: undefined reference to `QApplication::QApplication(int&, char**)'
main.o(.text+0x31): In function `main':
: undefined reference to `QString::QString(char const*)'
main.o(.text+0x45): In function `main':
: undefined reference to `QPushButton::QPushButton(QString const&, QWidget*, char const*)'
main.o(.text+0x5d): In function `main':
: undefined reference to `QString::shared_null'
main.o(.text+0x68): In function `main':
: undefined reference to `QStringData::deleteSelf()'
main.o(.text+0x77): In function `main':
: undefined reference to `QPushButton::resize(int, int)'
main.o(.text+0x80): In function `main':
: undefined reference to `QApplication::setMainWidget(QWidget*)'
main.o(.text+0x88): In function `main':
: undefined reference to `QWidget::show()'
main.o(.text+0x90): In function `main':
: undefined reference to `QApplication::exec()'
main.o(.text+0x9b): In function `main':
: undefined reference to `QPushButton::~QPushButton()'
main.o(.text+0xa3): In function `main':
: undefined reference to `QApplication::~QApplication()'
main.o(.text+0xc7): In function `main':
: undefined reference to `QString::shared_null'
main.o(.text+0xd2): In function `main':
: undefined reference to `QStringData::deleteSelf()'
main.o(.text+0xe3): In function `main':
: undefined reference to `QApplication::~QApplication()'
main.o(.text+0xf7): In function `main':
: undefined reference to `QPushButton::~QPushButton()'
main.o(.gnu.linkonce.r._ZTV6QGList+0xc): undefined reference to `QGList::clear()'
main.o(.gnu.linkonce.r._ZTV6QGList+0x10): undefined reference to `QGList::~QGList()'
main.o(.gnu.linkonce.r._ZTV6QGList+0x14): undefined reference to `QGList::~QGList()'
main.o(.gnu.linkonce.r._ZTV6QGList+0x18): undefined reference to `QPtrCollection::newItem(void*)'
main.o(.gnu.linkonce.r._ZTV6QGList+0x20): undefined reference to `QGList::compareItems(void*, void*)'
main.o(.gnu.linkonce.r._ZTV6QGList+0x24): undefined reference to `QGList::read(QDataStream&, void*&)'
main.o(.gnu.linkonce.r._ZTV6QGList+0x28): undefined reference to `QGList::write(QDataStream&, void*) const'
main.o(.gnu.linkonce.r._ZTI6QGList+0x8): undefined reference to `typeinfo for QPtrCollection'
collect2: ld returned 1 exit status
make: *** [qt] Error 1
Iv done many searches and i cant figure out why this wont work.

Thanks in advance,
jordan
 
Old 01-15-2005, 04:09 AM   #2
omes
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Hi.

First i must say i know nether Qt nor c++, and you should have postet this is programming(because most people there can answer much better than i do.)
It looks like it's something wrong with your code. Try to just compile some code from a tutorial, and see if it works..

Good luck

- omes
 
Old 01-15-2005, 04:40 AM   #3
__J
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The code looks ok, looks like qmake isnt finding the libs it needs. is $QTDIR/lib in /etc/ld.so.conf and have you run ldconfig since? also is $QTDIR set to the root of the qt installation?

Last edited by __J; 01-15-2005 at 04:42 AM.
 
Old 01-15-2005, 04:46 AM   #4
omes
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__J: I have everything properly installed, and i get the same errors as the threadstarter..

- omes
 
Old 01-15-2005, 05:03 AM   #5
__J
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Omes, where do you have qt installed?

jordban, make sure /home/jordban/qt3/lib is in your LD_LIBRARY_PATH

I entered the code and it compiled fine on my machine (with qt-3.3.3).

you should see it linking with qt ( -lqt-mt ) in the linking output. If you look at jordban's post above, it never links with it.

Last edited by __J; 01-15-2005 at 05:05 AM.
 
Old 01-15-2005, 05:05 AM   #6
omes
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qt: /usr/lib/qt
 
Old 01-15-2005, 05:08 AM   #7
__J
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did you compile it yourself or is it the original slack package. check /etc/profile.d/ for qt.sh and make sure /usr/lib/qt3/lib is in /etc/ld.so.conf ( the slack package should have taken care of this for you).
 
Old 01-15-2005, 05:10 AM   #8
omes
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it's the original slackware package. I'm going to install it myself now.

btw, there was no /usr/lib/qt3/lib in it

Last edited by omes; 01-15-2005 at 05:12 AM.
 
Old 01-15-2005, 05:11 AM   #9
__J
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double check for the two things mentioned above and try it again ( I'm using the slack 10 package and after qmake -project, qmake, make it compiled and linked without a problem).
 
Old 01-15-2005, 05:17 AM   #10
omes
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I don't have qt3 installed..
Guess that *might* be the threadstartes problem as well. As we get the exact same output when we try to compile to program...
 
Old 01-15-2005, 05:19 AM   #11
__J
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looks like he compiled it himself because its picking up the includes and compiles but fails at the linking stage. Also jordban, if you compiled it yourself did you include thread support?
 
Old 01-15-2005, 08:28 AM   #12
omes
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I've compiled it myself with thread support. I've checked up on the things you've said. I'm catching the package from slackware.com now.
 
Old 01-15-2005, 08:45 AM   #13
omes
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i didn't get it to work properly even with the slackware version of qt3..

- omes
 
Old 01-15-2005, 06:53 PM   #14
__J
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wait, did you compile it or install the slackware package?
If compiling, it has to be done a certain way (its not a standard ./configure,make, and make install) as for the standard slackware package, it sets up the environmental variables and library link paths for you so you shouldn't have many problems with that. Just for reference, here's how I compile qt:


export QTDIR=$PWD
export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH
export PATH=$QTDIR/bin:$PATH

./configure -prefix /opt/qt-3.3.3 -qt-gif -system-libjpeg -system-zlib -system-libpng -system-libmng -thread -no-exceptions

make ( or make sub-tools if you don't want the examples and such)
checkinstall (to make a slack package)

after its finished add:

/opt/qt-3.3.3/lib

to /etc/ld.so.conf

and open /etc/profile with a text editor and add the following line:

export QTDIR=/opt/qt-3.3.3

save and exit, then log out and back in (or source /etc/profile) and you shouldn't have any problems.

But the slack package is the easiest way to go by far.
 
Old 01-15-2005, 06:58 PM   #15
omes
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ok, ill try this first ting in the morning.

- omes
 
  


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