Ilyen szépség van nálam a /usr/include/fcntl.h-ban:
#ifndef __USE_FILE_OFFSET64
extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
#else
# ifdef __REDIRECT
extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
__nonnull ((1));
# else
# define open open64
# endif
#endif
#ifdef __USE_LARGEFILE64
extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
#endif