Undefined symbol in static library, but exists when in same VS solution

Question

I have a weird linker error that I can't seem to straighten out. This project is actually a Windows port of our system on Linux, so we know everything is working before the port to Windows.

I'm compiling FTGL (OpenGL font lib) as a static library using VS2013 (compiles fine) and I'm using that static lib in a DLL. However, I get linker errors saying it cannot find symbols that are, from what I can tell, there:

Error   1   error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall FTPoint::FTPoint(void)" (__imp_??0FTPoint@@QAE@XZ) referenced in function "public: virtual void __thiscall FPSCounter::draw(class Projector const *)" (?draw@FPSCounter@@UAEXPBVProjector@@@Z)  E:\Desktop\libWCLVS\fpsCounter\fpsCounter.obj   fpsCounter

Error   2   error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall FTPoint::FTPoint(double,double,double)" (__imp_??0FTPoint@@QAE@NNN@Z) referenced in function "public: virtual void __thiscall FPSCounter::draw(class Projector const *)" (?draw@FPSCounter@@UAEXPBVProjector@@@Z)   E:\Desktop\libWCLVS\fpsCounter\fpsCounter.obj   fpsCounter

"dumpbin.exe /symbols" on the FTGL static lib shows the following (amongst the rest):

1E5 00000000 SECT10 notype ()    External     | ??0FTPoint@@QAE@XZ (public: __thiscall FTPoint::FTPoint(void))

1E6 00000000 SECTE  notype ()    External     | ??0FTPoint@@QAE@NNN@Z (public: __thiscall FTPoint::FTPoint(double,double,double))

Now so far this has been compiling the static library and my DLL in separate VS solutions (both debug builds). If I import the existing static lib VS project into my DLL solution and create a reference to it via the project's Common Properties -> References, the DLL compiles, links and executes fine (also as debug build). This seems odd to me, as since I'm using the same project in a different solution, it will be compiling the same and thus I should have the same undefined symbols.

Obviously VS is doing something different in linking them when in same solution versus exporting the lib and then linking against it. Does anyone know why I would be getting this kind of behaviour and what I could do try and resolve it?

Answer 1

Ah! Thanks rpress, I had looked at FTGL_LIBRARY_STATIC and checked it was defined in the FTGL project, but it wasn't defined in my application that was including the FTGL header and thus my program was going to do the dllimport. Just added the FTGL_LIBRARY_STATIC to my application's project and it all works. Thanks!