Function semq_diff_within 

pub unsafe extern "C" fn semq_diff_within(
    diff: *const semq_diff_t,
    floor: *const semq_floor_t,
    out: *mut c_int,
    err: *mut semq_error_t,
) -> semq_status_t

*out = 1 iff the diff is within the floor (exact integer arithmetic). The floor must match the diff’s config, id kind and reference state_id (SEMQ_ERR_INCOMPATIBLE otherwise).