Visual Studio 2015

Unresolved external symbol since migration to_X64

Our Dll has Error LNK2001 unresolved external symbol _DllRegisterServer@0 error since we did the Migration To X64

we need this function for registration with regsv32 therefore we want to export this function with

# pragma comment(linker, "/EXPORTllRegisterServer=_DllRegisterServer@0,PRIVATE")


how can it be that we have the unresolved exernal Symbol after migration to X64 which worked for X86 with the same code