int isamh_alloc_block (ISAMH is, int cat);
void isamh_release_block (ISAMH is, int cat, int pos);
int isamh_read_block (ISAMH is, int cat, int pos, char *dst);
int isamh_alloc_block (ISAMH is, int cat);
void isamh_release_block (ISAMH is, int cat, int pos);
int isamh_read_block (ISAMH is, int cat, int pos, char *dst);