Is SuSE 64 bit ?

Does anybody know if SuSE 64 bit system is really 64 bit code? I can't seem to get any response from SuSE staff regarding the questions: 1: If I define int i; and real x; do I get 64 bit integer and float if compiled under 64? 2: Where does one find the definitions in the SuSE system? For example, where is the definition for the structure of XSizeHints ? Where is the definition of the function prototypes for the 64 bit functions? Maybe the 'average' programmer can ignore such issues, but I want to use FORTRAN to do the number crunching and I need to know if I should pass an integer(KIND=4) or integer(KIND=8) Regards, Colin