void isc_release_block (ISAMC is, int cat, int pos);
int isc_read_block (ISAMC is, int cat, int pos, char *dst);
int isc_write_block (ISAMC is, int cat, int pos, char *src);
void isc_release_block (ISAMC is, int cat, int pos);
int isc_read_block (ISAMC is, int cat, int pos, char *dst);
int isc_write_block (ISAMC is, int cat, int pos, char *src);