pub type subd_ex_vft = Option<unsafe extern "C" fn(diagoffx: doff_t, diagx: diag_t, transx: trans_t, m: dim_t, n: dim_t, x: *const c_void, rs_x: inc_t, cs_x: inc_t, y: *mut c_void, rs_y: inc_t, cs_y: inc_t, cntx: *const cntx_t, rntm: *mut rntm_t)>;
