Nothing works !

[Amoliane]

Hello !

I am using Qt 5.0.2 on ubuntu (12) and I wanted to use qwt on it but it definitely does not work. Do I have to uninstall everything and start again from scratch ?

Qt is installed in /opt/Qt5.0.2 ; I have installed it manually.
I have installed qwt 6.1.0 (which is in /usr/local/ as default) but I can't even use the library. When I try to, the files compiles but "The program has unexpectedly finished."
So maybe I have a wrong installation of the library.

As well, when I start QtCreator, I have this warning : " Warning: Kit file version 0 not supported, cannot restore kits!" which makes me wonder if I have changed something I shouldn't have while trying to add qwt...

Can somebody help me please ?

Camille.

[wysota]

When I try to, the files compiles but "The program has unexpectedly finished."
So maybe I have a wrong installation of the library.

No, you have bugs in your code.

[Amoliane]

No, you have bugs in your code.

I have only with qwt... When I only do that :

#include <QApplication>
#include <qwt/qwt_compass.h>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    QwtCompass compass;
    compass.show();
 
    return a.exec();
}

#include <QApplication>
#include <qwt/qwt_compass.h>

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

    QwtCompass compass;
    compass.show();
    
    return a.exec();
}

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I have the same result. I have no problem with all my C++ ; it is only qwt which I cannot use. Can you understand why ?

And I would really like to have this library include in the designer ; I don't why the plugin fails.

[Amoliane]

Is there really anybody who can help me ? I need qwt... :'(

[wysota]

What does your .pro file look like?

[Amoliane]

QT       += core gui
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
TARGET = test
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp
 
HEADERS  += mainwindow.h
 
FORMS    += mainwindow.ui
 
#qwt
CONFIG += qwt
 
unix|win32: LIBS += -L$$PWD/../../../../../usr/local/qwt-6.1.0/lib/ -lqwt
 
INCLUDEPATH += $$PWD/../../../../../usr/local/qwt-6.1.0/include
DEPENDPATH += $$PWD/../../../../../usr/local/qwt-6.1.0/include

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = test
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

#qwt
CONFIG += qwt

unix|win32: LIBS += -L$$PWD/../../../../../usr/local/qwt-6.1.0/lib/ -lqwt

INCLUDEPATH += $$PWD/../../../../../usr/local/qwt-6.1.0/include
DEPENDPATH += $$PWD/../../../../../usr/local/qwt-6.1.0/include

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mainwindow is nothing, it is only because I have created with QtCreator quickly and it has generated this class which I don't use.
Actually I want qwt for another project and this one is only to understand why it doesn't work.

Do you see something wrong ? If not, do you think the library could be badly installed and justified the error ?

[wysota]

The last four lines shouldn't be there. If you need them then apparently line #17 of your .pro file doesn't work which probably means you haven't read the readme file that comes with Qwt.

[Amoliane]

I have read many thing and still don't understand what I should do since there seems to be several ways to install qwt and I still don't know what should be manual and what should not be.

I have the same result when I remove those lines.

[wysota]

Don't read many things you don't need. Read the one thing you do need. Each Qwt source bundle comes with installation instructions. Just follow them.

[Amoliane]

It was the first thing I read and then I had trouble ! Well, I start again.

I confirm : I had read the README which told me to read the INSTALL which told me to read doc/html/qwtinstall.html which is the same thing as on the web which I have done... Trust me, this is the first time I ask a question ; usually I do everything by my own without problem. I may have made a mistake here ; that is pretty sure ! But I don't know what it is and I think there is something on that very page (qwtinstall.html) that I have not understood.

If you have explanation in french, it may be easier but I don't think the language is the problem here.

Thank you if you can help me.

[wysota]

So what exactly did you do after you read qwtinstall.html?

In particular did you follow the "Build and installation" section?

Did you follow the "Building a Qwt application" section?

Did you follow the "Running a Qwt application" section?

[Uwe]

Let me confirm Witold comments: it is not about criticizing - it is simply, that it is almost impossible to give reasonable support for a messed up configuration we don't know.

So try to revert everything you did so far with your Qwt installation and start from scratch doing it step by step. As soon as you have a problem don't try to help yourself without understanding what you are doing - ask here instead.

The installation guide is far from being perfect and I'm afraid it doesn't meet the requirements for all levels of experiences. But when you feel unsure better ask before following any of these cookbooks you find in the web - many of them are wrong most of them for different versions of Qwt.

Uwe

[Amoliane]

Hello,

I know it is not about criticizing. I was quite upset yesterday and I am sorry of that. I am glad there is somebody to answer my questions and I am frustrated not to be able to do it correctly by my own.
I am not in front of my own computer now (I come back tomorrow) but anyway, here is what I have done :

I have downloaded the tar.gz and untared it in the same folder.
Firstly I have not modified the .pri and called the lines proposed (blabla/qmake qwt.pro ; make ; sudo make install) and later, as it didn't seem to work, I have modified qwtconfig.pri to put the right thing instead of [QT_INSTALL_PREFIX] and redo the previous steps. (I don't know if it was to do or not.)

About the plug in, I have tried several things, you're right Uwe. I read that I had to put the files .so in some folders of Qt and I did it. I have also changed my .bashrc adding the lines of QT_PLUGIN_PATH with the right path instead of {QWT_ROOT}.

For the building, I have called "qmake -set QMAKEFEATURES ${QWT_ROOT}/features" but I am not sure of what it does.
I have added "CONFIG += qwt" in the .pro and I thought I had to add the library the traditionnal way too but you already told me I was wrong doing that.

I have thought of doing the other way, using "include ( ${QWT_ROOT}/features/qwt.prf )" but I have not understood where I would add this. So I haven't tried it.

For running the application, I wanted to do it directly with QtCreator but it may not be possible.

I wait for your reactions and tomorrow morning I fix all that ! :-)

Thank you very much for your answers.

[wysota]

Most probably you don't need to modify qwtconfig.pri. [QT_INSTALL_PREFIX] is one of predefined variables qmake understands and it expands to your Qt installation directory. Running qmake && make install should get you a properly built Qwt installation. Then either dump the designer plugin where it should reside (which is [QT_INSTALL_PLUGINS]/designer) or add the directory containing the "designer" directory containing the plugin into QT_PLUGIN_PATH as qwtinstall.html advises. Then you can continue to the next steps described in the installation document.

[Amoliane]

Hello,

I am back from a week far from any computer and try again to use qwt. I still have the same problem : when I run my program, I have an error of pointer which occurs only if I use a qwt class.
I have redone the installation following the steps of qwtinstall.html.
I suppose I don't compile my code as I should. Or I may really have an installation problem but after having redone it carefully, I hope not !

I have entered "qmake -set QMAKEFEATURES ${QWT_ROOT}/features" in the console and added "CONFIG += qwt" in the .pro file.

Where could the problem come from ? What is my mistake ?

Thank you if you can help me.

[wysota]

What does qmake -query QMAKEFEATURES return?

[Amoliane]

It was :

qmake -query QMAKEFEATURES
/features

qmake -query QMAKEFEATURES
/features

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I have entered "qmake -set QMAKEFEATURES" with the right path and "qmake -query QMAKEFEATURES" now return it but I still have my problem. Should I have replaced {QWT_ROOT} somewhere else before ? Or maybe I shouldn't have changed it and it is not normal that {QWT_ROOT} is not understood ?

[wysota]

Yes, you should replace it with the path to your Qwt installation.

[Amoliane]

I did it, as I said, and the problem remains. I haven't found if I had to change it somewhere else.

One day, this will work !

[ChrisW67]

To confirm.
You have Qwt 6.1 built with Qt5 and installed under /usr/local.

So this is what you get:

chrisw@newton ~ $ qmake -query QMAKEFEATURES
/usr/local/qwt-6.1.0/features

chrisw@newton ~ $ qmake -query QMAKEFEATURES
/usr/local/qwt-6.1.0/features

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and you have a pro file like:

QT       += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
TARGET = test
TEMPLATE = app
SOURCES += main.cpp\
        mainwindow.cpp
HEADERS  += mainwindow.h
FORMS    += mainwindow.ui
CONFIG += qwt

QT       += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = test
TEMPLATE = app
SOURCES += main.cpp\
        mainwindow.cpp
HEADERS  += mainwindow.h
FORMS    += mainwindow.ui
CONFIG += qwt

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and a basic program like the one you posted earlier. Your code compiles without warning or error, but "doesn't work" when started..

If so, exactly what does "doesn't work" mean?