[Insight-users] Problems building the example from "Introduction to FLTK" by Luis Ibanez

[Luis Ibanez]

Hi Lino,


"Unresolved external" almost always means that you are
missing to link with a library. The list of unresolved
symbols usually indicates what libraries are missing.

In your case, the missing symbols are fundamental
FLTK ones, like Fl::run(). This means that you are
missing the basic FLTK libraries.

Simply add the following CMake command to your
CMakeList.txt file.


TARGET_LINK_LIBRARIES( TestCalculator ${FLTK_LIBRARIES})


Then Rerun CMake, and rebuild your project.


BTW,
September 2001 was long time ago,   :-)

You will find more convenient to use the more recent material
we prepared for the ITK tutorials:

       http://www . itk . org/HTML/Tutorials . htm


Regards,



   Luis


-------------------
Lino Ramirez wrote:
> Hello,
> 
>  
> 
> I am trying to build the Example from “Introduction to FLTK” by Luis 
> Ibanez (Sept 11, 2001) using Visual C++ 6.0.
> 
>  
> 
> Here are the errors I am getting
> 
>  
> 
> --------------------Configuration: TestCalculator - Win32 
> Debug--------------------
> 
> Compiling...
> 
> main.cxx
> 
> Linking...
> 
> main.obj : error LNK2001: unresolved external symbol "public: static int 
> __cdecl Fl::run(void)" (?run at Fl@@SAHXZ)
> 
> main.obj : error LNK2001: unresolved external symbol "public: __thiscall 
> CalculatorGUI::CalculatorGUI(void)" (??0CalculatorGUI@@QAE at XZ)
> 
> main.obj : error LNK2001: unresolved external symbol "public: int 
> __thiscall Fl_Valuator::value(double)" (?value at Fl_Valuator@@QAEHN at Z)
> 
> main.obj : error LNK2001: unresolved external symbol "public: virtual 
> __thiscall CalculatorGUI::~CalculatorGUI(void)" (??1CalculatorGUI@@UAE at XZ)
> 
> Debug/TestCalculator.exe : fatal error LNK1120: 4 unresolved externals
> 
> Error executing link.exe.
> 
>  
> 
> ALL_BUILD - 5 error(s), 0 warning(s)
> 
>  
> 
> -------------------------------------------------------------------------------------------------
> 
>  
> 
> This is the CMakeLists.txt I am using
> 
> -------------------------------------------------------------------------------------------------
> 
> PROJECT( TestCalculator )
> 
>  
> 
> INCLUDE (${CMAKE_ROOT}/Modules/FindFLTK.cmake)
> 
>  
> 
> INCLUDE_DIRECTORIES(
> 
>   ${FLTK_INCLUDE_PATH}
> 
>  
> 
> )
> 
>  
> 
> ADD_EXECUTABLE( TestCalculator main.cxx )
> 
> -------------------------------------------------------------------------------------------------
> 
>  
> 
> Could anyone tell me where the problem is?
> 
>  
> 
> Thank you,
> 
>  
> 
> Lino Ramirez
> 
>  
> 
> P.S. Below is the CalculatorGUI.fld file.
> 
> -------------------------------------------------------------------------------------------------
> 
> # data file for the Fltk User Interface Designer (fluid)
> 
> version 1.0104
> 
> do_not_include_H_from_C
> 
> header_name {.h}
> 
> code_name {.cxx}
> 
> class CalculatorGUI {open : {public BaseCalculator}
> 
> } {
> 
>   Function {CalculatorGUI()} {open
> 
>   } {
> 
>     Fl_Window CalculatorPanel {open
> 
>       xywh {509 160 282 221}
> 
>       code0 {\#include "BaseCalculator.h"}
> 
>       class CalculatorGUI visible
> 
>     } {
> 
>       Fl_Value_Input OperandAInputValue {
> 
>         label {A:}
> 
>         callback {SetOperandB( o->value );}
> 
>         xywh {25 25 25 25} align 132 maximum 10
> 
>       }
> 
>       Fl_Value_Input OperandBInputValue {
> 
>         label {B:}
> 
>         callback {SetOperandB( o->value );}
> 
>         xywh {105 25 25 25} align 68
> 
>       }
> 
>       Fl_Button {} {
> 
>         label {+}
> 
>         callback {Add();}
> 
>         xywh {60 25 25 25}
> 
>       }
> 
>       Fl_Value_Output ResultOutputValue {
> 
>         label {=}
> 
>         xywh {145 25 25 25}
> 
>       }
> 
>     }
> 
>   }
> 
>   Function {~CalculatorGUI()} {open return_type virtual
> 
>   } {}
> 
>   Function {show()} {open return_type virtual
> 
>   } {}
> 
>   Function {hide()} {open selected return_type virtual
> 
>   } {}
> 
> }
> 
> -------------------------------------------------------------------------------------------------
> 
>  
> 
>  
>