/win64 switch
The /win64 switch directs the MIDL compiler to generate stub files, or a type library file, for a 64-bit environment.
Note
This switch is obsolete. Please use the /ia64 or /amd64 switch instead. The /win64 switch is equivalent to the /ia64 switch.
midl /win64
This switch has no parameters.
The /win64 switch is equivalent to setting the /env switch to win64.
Note
It is not possible to use MIDL.exe to produce a 64bit tlb on Windows 2000.