Qwt plot problem on compile

[sincnarf]

Hello,
I am trying to use Qwt plot and I have successfully installed it and set the needed directories for LD_LIBRARY_PATH environment variable. When I used QtDesigner, the Qwt widgets are available for use so i tried to place a QwtPlot in my ui.

This is the error when I try to compile

release/mainwindow.o: In function `Ui_mainwindow::setupUi(QMainWindow*)':
mainwindow.cpp.text._ZN13Ui_mainwindow7setupUiEP11QMainWindow[Ui_mainwindow::setupUi(QMainWindow*)]+0x2ed5): undefined reference to `QwtPlot::QwtPlot(QWidget*)'
mainwindow.cpp.text._ZN13Ui_mainwindow7setupUiEP11QMainWindow[Ui_mainwindow::setupUi(QMainWindow*)]+0x30b4): undefined reference to `QwtPlot::QwtPlot(QWidget*)'
mainwindow.cpp.text._ZN13Ui_mainwindow7setupUiEP11QMainWindow[Ui_mainwindow::setupUi(QMainWindow*)]+0x327d): undefined reference to `QwtPlot::QwtPlot(QWidget*)'
release/moc_qwt_plot.o: In function `QwtPlot::qt_metacall(QMetaObject::Call, int, void**)':

[jpn]

Did you actually link against Qwt? Just like the examples do (see examples.pri).

[sincnarf]

Did you actually link against Qwt? Just like the examples do (see examples.pri).

slightly solved this. by repeatedly exporting the lib dir to LD_LIBRARY_PATH. Although sometimes my LD_LIBRARY_PATH Environment variable suddenly disappears in my non-root account in ubuntu