Does anybody know what this error is?

I'm getting the error below, when i build my project. is this familiar to anybody?



g++ -c -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -I"..\..\..\..\Qt2\2010.04\qt\include\QtCore" -I"..\..\..\..\Qt2\2010.04\qt\include\QtGui" -I"..\..\..\..\Qt2\2010.04\qt\include" -I"..\..\..\..\Qt2\2010.04\qt\include\ActiveQt" -I"debug" -I"..\Assignment1Q1" -I"." -I"..\..\..\..\Qt2\2010.04\qt\mkspecs\win32-g++" -o debug\moc_bookwriter.o debug\moc_bookwriter.cpp
g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -Wl,-subsystem,console -mthreads -Wl -o debug\Assignment1Q1.exe debug/main.o debug/book.o debug/bookinput.o debug/bookwriter.o debug/moc_bookinput.o debug/moc_bookwriter.o -L"c:\Qt2\2010.04\qt\lib" -lQtGuid4 -lQtCored4
mingw32-make[1]: Leaving directory `C:/UNISA MODULES/COS3711/ASSIGNMENTS/Assignment1Q1-build-desktop'
mingw32-make: Leaving directory `C:/UNISA MODULES/COS3711/ASSIGNMENTS/Assignment1Q1-build-desktop'
debug/moc_bookinput.o:C:\UNISA MODULES\COS3711\ASSIGNMENTS\Assignment1Q1-build-desktop/debug/moc_bookinput.cpp:85: undefined reference to `bookInput::getDate()'
collect2: ld returned 1 exit status
mingw32-make[1]: *** [debug\Assignment1Q1.exe] Error 1
mingw32-make: *** [debug] Error 2
The process "C:/Qt2/2010.04/mingw/bin/mingw32-make.exe" exited with code %2.
Error while building project Assignment1Q1 (target: Desktop)
When executing build step 'Make'

Do you have a definition for bookInput::getDate()? Tell us more information and maybe show some code, anyway my guess is that you added that slot and didn't run qmake before you tried to build your project.