Unresolved external symbol with x64 flag c++
I have a VS2008 C++ project which currently I compiled on VS2010.
it contains a dll and execution GUI project.

With x64 flag the dll is build without any errors but the GUI has some LNK errors to function that are in the dll. "unresolved external symbol..." (error LNK 2019 and 2001)
with Win32 flag there is no LNK errors.

I'm running on x64 OS.

Any help please?
Unresolved external symbol with x64 flag c++
===

I have a VS2008 C++ project which currently I compiled on VS2010.
it contains a dll and execution GUI project.

With x64 flag the dll is build without any errors but the GUI has some LNK errors to function that are in the dll. "unresolved external symbol..." (error LNK 2019 and 2001)
with Win32 flag there is no LNK errors.

I'm running on x64 OS.

Any help please?