How exactly to specify that FILE* is 64bit, regardless if I define the appl to be 32 or 64 bit?

[DW7]

Is it defined by the language (like in some header file) or the environment of development?
I intend to try it with VS 2013 on a Win 7 64 bit.
Thanks

[Little Bobby Tables]

im sorry could you please expand upon what you mean? because the file structure isnt 32 or 64 bit