Compile error - Qwt and Qt Designer

[yoshi]

I've installed qwt and can compile & run all the qwt examples
in C:\qwt-5.0.2\examples. I use Eclipse with MinGW on Windows XP.

When I compile the very simple program called qwt_designer
(shown below), I get the following error.
make: *** [release] Error 2 qwt_designer line 0
make[1]: *** [release\qwt_designer.exe] Error 1 qwt_designer line 0

I only have one push button and one qwt plot object in the .ui file.
The project compiles and runs fine
- if I remove the qwt plot object from the .ui file
or
- if I do not declare the slots (line 18 of qwt_designer.h)
which seems very weird to me...

main.cpp

#include <QtGui>
#include <QApplication>
 
#include "qwt_designer.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    qwt_designer w;
    w.show();
    a.connect(&a, SIGNAL(lastWindowClosed()), &a, SLOT(quit()));
    return a.exec();
}

#include <QtGui>
#include <QApplication>

#include "qwt_designer.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    qwt_designer w;
    w.show();
    a.connect(&a, SIGNAL(lastWindowClosed()), &a, SLOT(quit()));
    return a.exec();
}

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qwt_designer.cpp

#include "qwt_designer.h"
 
qwt_designer::qwt_designer(QWidget *parent)
    : QWidget(parent)
{
	ui.setupUi(this);
}
 
qwt_designer::~qwt_designer()
{
 
}

#include "qwt_designer.h"

qwt_designer::qwt_designer(QWidget *parent)
    : QWidget(parent)
{
	ui.setupUi(this);
}

qwt_designer::~qwt_designer()
{

}

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qwt_designer.h

#ifndef QWT_DESIGNER_H
#define QWT_DESIGNER_H
 
#include <QtGui/QWidget>
#include "ui_qwt_designer.h"
 
class QTcpSocket;
 
 
class qwt_designer : public QWidget
{
    Q_OBJECT
 
public:
    qwt_designer(QWidget *parent = 0);
    ~qwt_designer();
 
public slots:	// <-- No error if this line is commented out
    void on_myButton_pressed();
 
private:
    Ui::qwt_designerClass ui;
};
 
#endif // QWT_DESIGNER_H

#ifndef QWT_DESIGNER_H
#define QWT_DESIGNER_H

#include <QtGui/QWidget>
#include "ui_qwt_designer.h"

class QTcpSocket;


class qwt_designer : public QWidget
{
    Q_OBJECT

public:
    qwt_designer(QWidget *parent = 0);
    ~qwt_designer();

public slots:	// <-- No error if this line is commented out
    void on_myButton_pressed();
 
private:
    Ui::qwt_designerClass ui;
};

#endif // QWT_DESIGNER_H

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qwt_designer.pro

include(qwt_tools.pri)
TEMPLATE = app
TARGET = qwt_designer
QT += core \
    gui
HEADERS += qwt_designer.h
SOURCES += main.cpp \
    qwt_designer.cpp
FORMS += qwt_designer.ui

include(qwt_tools.pri)
TEMPLATE = app
TARGET = qwt_designer
QT += core \
    gui
HEADERS += qwt_designer.h
SOURCES += main.cpp \
    qwt_designer.cpp
FORMS += qwt_designer.ui

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qwt_tools.pri - taken from the .pri file in qwt example.

QWT_ABS_PATH = C:/qwt-5.0.2
include( $$QWT_ABS_PATH/qwtconfig.pri )
TEMPLATE = app
MOC_DIR = moc
OBJECTS_DIR = obj
INCLUDEPATH += $$QWT_ABS_PATH/src
DEPENDPATH += $$QWT_ABS_PATH/src
unix:LIBS += -L$$QWT_ABS_PATH/lib \
    -lqwt
win32:QwtDll:DEFINES += $$QT_DLL \
    QWT_DLL
contains(CONFIG, QwtDll) { 
    win32-msvc:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-msvc.net:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-msvc2005:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-g++:LIBS += -L \
        $$QWT_ABS_PATH/lib \
        -lqwt
}
else { 
    win32-msvc:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-msvc.net:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-msvc2005:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-g++:LIBS += -L \
        $$QWT_ABS_PATH/lib \
        -lqwt
}

QWT_ABS_PATH = C:/qwt-5.0.2
include( $$QWT_ABS_PATH/qwtconfig.pri )
TEMPLATE = app
MOC_DIR = moc
OBJECTS_DIR = obj
INCLUDEPATH += $$QWT_ABS_PATH/src
DEPENDPATH += $$QWT_ABS_PATH/src
unix:LIBS += -L$$QWT_ABS_PATH/lib \
    -lqwt
win32:QwtDll:DEFINES += $$QT_DLL \
    QWT_DLL
contains(CONFIG, QwtDll) { 
    win32-msvc:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-msvc.net:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-msvc2005:LIBS += $$QWT_ABS_PATH/lib/qwt5.lib
    win32-g++:LIBS += -L \
        $$QWT_ABS_PATH/lib \
        -lqwt
}
else { 
    win32-msvc:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-msvc.net:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-msvc2005:LIBS += $$QWT_ABS_PATH/lib/qwt.lib
    win32-g++:LIBS += -L \
        $$QWT_ABS_PATH/lib \
        -lqwt
}

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I'd appreciate your help.

[yoshi]

qmake & make from the Qt 4.3.3 Command prompt showed the following:

obj/moc_qwt_designer.o(.text+0xb5):moc_qwt_designer.cpp: undefined reference to
`qwt_designer::on_myButton_pressed()'
collect2: ld returned 1 exit status
mingw32-make[1]: *** [release\qwt_designer.exe] Error 1

obj/moc_qwt_designer.o(.text+0xb5):moc_qwt_designer.cpp: undefined reference to
`qwt_designer::on_myButton_pressed()'
collect2: ld returned 1 exit status
mingw32-make[1]: *** [release\qwt_designer.exe] Error 1

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Adding the following to qwt_desginer.cpp has fixed the problem.

void qwt_designer::on_myButton_pressed()
{
	;
}

void qwt_designer::on_myButton_pressed()
{
	;
}

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It's interesting that the combination of "slots in the header file" and "the Qwt plot object in the .ui file" forced the implementation of the function on_myButton_pressed().

[openware]

I have the similar problem with yoshi too, but not quite the same. Here is my error message dumped out when I was compiling the similar simple program. Thought I did as yoshi said, the problem still exists. It seems like that the moc didn't work. How can I fix the problem?

mingw32-make -f Makefile.Debug all
mingw32-make[1]: Entering directory `C:/Users/owr/Desktop/Trash/qwt-6.0.0-rc4/examples/curvdemo2'
compiling curvdemo2.cpp
In file included from ..\..\src/qwt_scale_div.h:14,
from ..\..\src/qwt_plot_seriesitem.h:15,
from ..\..\src/qwt_plot_curve.h:14,
from curvdemo2.h:2,
from curvdemo2.cpp:6:
..\..\src/qwt_interval.h:270: warning: 'bool QwtInterval::isValid() const' redeclared without dllimport attribute after
being referenced with dll linkage

In file included from curvdemo2.cpp:6:
curvdemo2.h:17: error: expected ':' before 'slots'
curvdemo2.h:18: error: expected primary-expression before 'void'
curvdemo2.h:18: error: ISO C++ forbids declaration of 'slots' with no type
curvdemo2.h:18: error: expected ';' before 'void'
curvdemo2.cpp:33: error: no 'void MainWin::show_a()' member function declared in class 'MainWin'
mingw32-make[1]: *** [debug/curvdemo2.o] Error 1
mingw32-make[1]: Leaving directory `C:/Users/owr/Desktop/Trash/qwt-6.0.0-rc4/examples/curvdemo2'
mingw32-make: *** [debug-all] Error 2
curvdemo2.h:17: error: expected ':' before 'slots'
curvdemo2.h:18: error: expected primary-expression before 'void'
curvdemo2.h:18: error: ISO C++ forbids declaration of 'slots' with no type
curvdemo2.h:18: error: expected ';' before 'void'
curvdemo2.cpp:33: error: no 'void MainWin::show_a()' member function declared in class 'MainWin'

PS: There is nothing wrong when I did this under Linux...