title: Linker errors in Qt Creator 2.4.1 associated with CImg library
body: <p>I wrote a small image processing algorithm using the CImg library and bundled it in a command line application using Visual C++ Express. Everything compiled error free and ran well, until the engineer in charge of the project decided he wanted a GUI. So I went to Qt and Qt creator. The GUI functioned fine by itself, but all hell breaks loose when I move my image processing algorithm over. </p>
  
  <pre><code>mainwindow.obj : error LNK2019: unresolved external 
  symbol__imp__SHGetSpecialFolderPathA@16 referenced in function "char const * __cdecl 
  cimg_library::cimg::programfiles_path(char const * const,bool)" 
  (?programfiles_path@cimg@cimg_library@@YAPBDQBD_N@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol 
  __imp__EnumDisplaySettingsW@12 referenced in function "public: static int __cdecl  
  cimg_library::CImgDisplay::screen_width(void)" 
  (?screen_width@CImgDisplay@cimg_library@@SAHXZ)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__DestroyWindow@4    
  referenced in function "public: struct cimg_library::CImgDisplay &amp; __thiscall  
  cimg_library::CImgDisplay::assign(void)" 
  (?assign@CImgDisplay@cimg_library@@QAEAAU12@XZ)
  
  mainwindow.obj : error LNK2019: unresolved external symbol   
  __imp__ChangeDisplaySettingsW@8 referenced in function "public: void __thiscall 
  cimg_library::CImgDisplay::_desinit_fullscreen(void)" 
  (?_desinit_fullscreen@CImgDisplay@cimg_library@@QAEXXZ)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__SetWindowPos@28 
  referenced in function "public: struct cimg_library::CImgDisplay &amp; __thiscall 
  cimg_library::CImgDisplay::resize(int,int,bool)" 
  (?resize@CImgDisplay@cimg_library@@QAEAAU12@HH_N@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__AdjustWindowRect@12 
  referenced in function "public: struct cimg_library::CImgDisplay &amp; __thiscall 
  cimg_library::CImgDisplay::resize(int,int,bool)" 
  (?resize@CImgDisplay@cimg_library@@QAEAAU12@HH_N@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__DispatchMessageW@4 
  referenced in function "public: static unsigned long __stdcall 
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__GetMessageW@16 
  referenced in function "public: static unsigned long __stdcall 
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__SetWindowLongW@12 
  referenced in function "public: static unsigned long __stdcall 
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__GetDC@4 referenced 
  in function "public: static unsigned long __stdcall  
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol 
  __imp__SetForegroundWindow@4 referenced in function "public: static unsigned long 
  __stdcall cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__GetWindowRect@8 
  referenced in function "public: static unsigned long __stdcall 
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__CreateWindowExA@48 
  referenced in function "public: static unsigned long __stdcall 
  cimg_library::CImgDisplay::_events_thread(void *)" 
  (?_events_thread@CImgDisplay@cimg_library@@SGKPAX@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__DefWindowProcW@16 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__ShowCursor@4 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__TrackMouseEvent@4 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__PeekMessageW@20 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__ShowWindow@8 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__GetWindowLongW@8 
  referenced in function "public: static long __stdcall 
  cimg_library::CImgDisplay::_handle_events(struct HWND__ *,unsigned int,unsigned 
  int,long)" (?_handle_events@CImgDisplay@cimg_library@@SGJPAUHWND__@@IIJ@Z)
  
  mainwindow.obj : error LNK2019: unresolved external symbol __imp__SetDIBitsToDevice@48 
  referenced in function "public: struct cimg_library::CImgDisplay &amp; __thiscall 
  cimg_library::CImgDisplay::paint(void)" (?paint@CImgDisplay@cimg_library@@QAEAAU12@XZ)
  
  debug\final.exe : fatal error LNK1120: 20 unresolved externals
  
  NMAKE : fatal error U1077: '"c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC  
  \BIN\link.EXE"' : return code '0x460'
  
  Stop.
  
  NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC  
  \BIN\nmake.exe"' : return code '0x2'
  
  Stop.
  </code></pre>
  
  <p>My problem now, is I have no idea why I'm having linker trouble. The CImg library is a single H file. It's part of the project and included. I know Qt Creator needs libraries added to the project file, but what is there to add? My library is already listed under headers.</p>
  
  <p>Here is the project file.</p>
  
  <pre><code>QT       += core gui
  
  TARGET = final
  TEMPLATE = app
  
  
  SOURCES += main.cpp\
          mainwindow.cpp
  
  HEADERS  += mainwindow.h \
      C:/includes/CImg.h
  
  FORMS    += mainwindow.ui
  
  INCLUDEPATH += C:\includes\
  </code></pre>
  
  <p>Thanks for the assistance, I'm primarily an embedded systems programmer, and working out of my C and assembly element is getting very frustrating.</p>