I am new to Qt and even more new to Qwt.

It is the first time I am using Qwt, and I can't compile it.

I am using QT Creator 2.1.80 (based on Qt 4.7.0) and have made a "MainWindow" in the graphic "Form" editor.


When I try to compile this , the error occurs in ui_mainwindow.h: 107: error: undefined reference to `QwtPlot::QwtPlot(QWidget*)'

line 107:
Qt Code:
  1. centralWidget = new QWidget(MainWindow);
  2. centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
  3. qwtKurva = new QwtPlot(centralWidget); // **** LINE 107 ****
  4. qwtKurva->setObjectName(QString::fromUtf8("qwtKurva"));
  5. qwtKurva->setEnabled(false);
  6. qwtKurva->setGeometry(QRect(10, 40, 521, 211));
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The code is generated automatically, so I don't know what is causing the problem.