using qwt in QT Creator gives error Collect2: ld returned 1 exit status

Starting: C:/Qt/2010.02.1/mingw/bin/mingw32-make.exe -w mingw32-make: Entering directory C:/Qt/2010.02.1/qt/qwt/qwt-5.2.1/textengines/data_plot' C:/Qt/2010.02.1/mingw/bin/mingw32-make -f Makefile.Release all mingw32-make[1]: Entering directoryC:/Qt/2010.02.1/qt/qwt/qwt-5.2.1/textengines/data_plot' linking ....\examples\bin\data_plot.exe c:/qt/2010.02.1/mingw/bin/../lib/gc开发者_如何学编程c/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lqwt5 collect2: ld returned 1 exit status mingw32-make[1]: Leaving directory C:/Qt/2010.02.1/qt/qwt/qwt-5.2.1/textengines/data_plot' mingw32-make: Leaving directoryC:/Qt/2010.02.1/qt/qwt/qwt-5.2.1/textengines/data_plot' mingw32-make[1]: * [....\examples\bin\data_plot.exe] Error 1 mingw32-make: * [release-all] Error 2 Exited with code 2. Error while building project data_plot When executing build step 'Make'

What might be the reason of such an error??

Thanks for any suggestion :)

The error message suggests that the qwt5 library was not found.

Check that your QWT library is indeed called qwt5.dll and that the linker is given the path to find that library (Check that there is a line reading LIBS += -L/path/to/qwt -lqwt5 in your .pro file).