C with LP 64

Sth may go wrong under LP64

good links here:
http://www.unix.org/version2/whatsnew/lp64_wp.html
http://www.unix.org/version2/whatsnew/login_64bit.html

Datatype	LP64	ILP64	LLP64	ILP32	LP32
char	8	8	8	8	8
short	16	16	16	16	16
_int32		32
int	32	64	32	32	16
long	64	64	32	32	32
long long			64
pointer	64	64	64	32	32