Unresolved external symbols...

[RealIndica]

under the d3d9.hpp file, there are two externals
extern LRESULT ImGui_ImplDX9_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam); extern inline void render();

I have no idea why, but they are marked as unresolved external symbols. This is what i get in the console:
Severity Code Description Project File Line Suppression State Error LNK1120 2 unresolved externals Ascienth_Gmod_v1 C:\Users\Leonl\source\repos\Ascienth_Gmod_v1\Debug\Ascienth_Gmod_v1.dll 1 Error LNK2019 unresolved external symbol "long __cdecl ImGui_ImplDX9_WndProcHandler(struct HWND__ *,unsigned int,unsigned int,long)" (?ImGui_ImplDX9_WndProcHandler@@YAJPAUHWND__@@IIJ@Z) referenced in function "long __stdcall detours::proc(struct HWND__ *,unsigned int,unsigned int,long)" (?proc@detours@@YGJPAUHWND__@@IIJ@Z) Ascienth_Gmod_v1 C:\Users\Leonl\source\repos\Ascienth_Gmod_v1\Ascienth_Gmod_v1\dllmain.obj 1 Error LNK2019 unresolved external symbol "void __cdecl render(void)" (?render@@YAXXZ) referenced in function "long __stdcall detours::present(struct IDirect3DDevice9 *,struct tagRECT const *,struct tagRECT const *,struct HWND__ *,struct _RGNDATA const *)" (?present@detours@@YGJPAUIDirect3DDevice9@@PBUtagRECT@@1PAUHWND__@@PBU_RGNDATA@@@Z) Ascienth_Gmod_v1 C:\Users\Leonl\source\repos\Ascienth_Gmod_v1\Ascienth_Gmod_v1\dllmain.obj 1

Any ideas? Im new to d3d hooking and i figured i should start from here.
Thanks.

[RealIndica]

#Update

Fixed the external symbol for the WndProcHandler -Added the win32 implementation header and cpp file.

Not sure about render though...