int wflag, int *firstp);
int cf_read (CFile cf, zint no, int offset, int nbytes, void *buf);
int cf_write (CFile cf, zint no, int offset, int nbytes, const void *buf);
int wflag, int *firstp);
int cf_read (CFile cf, zint no, int offset, int nbytes, void *buf);
int cf_write (CFile cf, zint no, int offset, int nbytes, const void *buf);