unresolved external symbol in eclipse cdt - c++

Question

I try to build cpp file using eclipse cdt. Linker throws "unresolved external symbol", however path to lib file that contains implementation for function is listed in LIB environment variable on Project properties->C/C++ Build->Environment
What am I doing wrong?
UPD I try to build file. There is lib RpcRT4.Lib on the path C:\Program Files\Microsoft SDKs\Windows\v7.0A\Lib\
And linker fails:
**** Build of configuration Debug for project test cpp ****
**** Internal Builder is used for build ****
link /debug /nologo /OUT:test cpp.exe main.obj
main.obj : error LNK2019: unresolved external symbol __imp__RpcStringFreeA#4 referenced in function "bool __cdecl Initialize_CreateWindowClass(void)"(?Initialize_CreateWindowClass##YA_NXZ)
main.obj : error LNK2019: unresolved external symbol __imp__RegisterClassA#4 referenced in function "bool __cdecl Initialize_CreateWindowClass(void)" (?Initialize_CreateWindowClass##YA_NXZ)
main.obj : error LNK2019: unresolved external symbol __imp__UuidToStringA#8 referenced in function "bool __cdecl Initialize_CreateWindowClass(void)" (?Initialize_CreateWindowClass##YA_NXZ)
main.obj : error LNK2019: unresolved external symbol __imp__UuidCreate#4 referenced in function "bool __cdecl Initialize_CreateWindowClass(void)" (?Initialize_CreateWindowClass##YA_NXZ)
main.obj : error LNK2019: unresolved external symbol __imp__DefWindowProcA#16 referenced in function "long __stdcall SkypeAPITest_Windows_WindowProc(struct HWND__ *,unsigned int,unsigned int,long)" (?SkypeAPITest_Windows_WindowProc##YGJPAUHWND__##IIJ#Z)
main.obj : error LNK2019: unresolved external symbol __imp__PostQuitMessage#4 referenced in function "long __stdcall SkypeAPITest_Windows_WindowProc(struct HWND__ *,unsigned int,unsigned int,long)" (?SkypeAPITest_Windows_WindowProc##YGJPAUHWND__##IIJ#Z)
main.obj : error LNK2019: unresolved external symbol __imp__UnregisterClassA#8 referenced in function "void __cdecl DeInitialize_DestroyWindowClass(void)" (?DeInitialize_DestroyWindowClass##YAXXZ)
main.obj : error LNK2019: unresolved external symbol __imp__CreateWindowExA#48 referenced in function "bool __cdecl Initialize_CreateMainWindow(void)" (?Initialize_CreateMainWindow##YA_NXZ)
main.obj : error LNK2019: unresolved external symbol __imp__DestroyWindow#4 referenced in function "void __cdecl DeInitialize_DestroyMainWindow(void)" (?DeInitialize_DestroyMainWindow##YAXXZ)
main.obj : error LNK2019: unresolved external symbol __imp__DispatchMessageA#4 referenced in function "void __cdecl Global_MessageLoop(void)" (?Global_MessageLoop##YAXXZ)
main.obj : error LNK2019: unresolved external symbol __imp__TranslateMessage#4 referenced in function "void __cdecl Global_MessageLoop(void)" (?Global_MessageLoop##YAXXZ)
main.obj : error LNK2019: unresolved external symbol __imp__GetMessageA#16 referenced in function "void __cdecl Global_MessageLoop(void)" (?Global_MessageLoop##YAXXZ)
main.obj : error LNK2019: unresolved external symbol __imp__PostMessageA#16 referenced in function "void __cdecl Global_InputProcessingThread(void *)" (?Global_InputProcessingThread##YAXPAX#Z)
main.obj : error LNK2019: unresolved external symbol __imp__SendMessageA#16 referenced in function "void __cdecl Global_InputProcessingThread(void *)" (?Global_InputProcessingThread##YAXPAX#Z)
main.obj : error LNK2019: unresolved external symbol __imp__RegisterWindowMessageA#4 referenced in function _main
test cpp.exe : fatal error LNK1120: 15 unresolved externals
Build error occurred, build is stopped
Time consumed: 2438 ms.
And environment settings for project

Answer 1

I'm not entirely clear on whether you've already done this based on the question, but just adding the directory to your linker's search path isn't enough for any compiler/linker I've ever used. There could be hundreds of different libraries in there, even different versions of the same library, and the linker has no idea which ones you do and don't want. You need to tell it, explicitly, to link against the library using the appropriate parameter.
It looks like you're using the Microsoft linker, which I've never used, so I can't help you with the specific flag but it should be easy enough to find what it is in the documentation if that's the issue. I presume Eclipse has a method of specifying this in the GUI as well which should be generic across the various compilers it supports.