BIGNUM *load_serial(char *serialfile, int create, ASN1_INTEGER **retai);
int save_serial(char *serialfile, char *suffix, BIGNUM *serial, ASN1_INTEGER **retai);
int rotate_serial(char *serialfile, char *new_suffix, char *old_suffix);
BIGNUM *load_serial(char *serialfile, int create, ASN1_INTEGER **retai);
int save_serial(char *serialfile, char *suffix, BIGNUM *serial, ASN1_INTEGER **retai);
int rotate_serial(char *serialfile, char *new_suffix, char *old_suffix);