Function vaQueryDisplayAttributes 

pub unsafe extern "C" fn vaQueryDisplayAttributes(
    dpy: VADisplay,
    attr_list: *mut VADisplayAttribute,
    num_attributes: *mut c_int,
) -> VAStatus

Query display attributes The caller must provide a “attr_list” array that can hold at least vaMaxNumDisplayAttributes() entries. The actual number of attributes returned in “attr_list” is returned in “num_attributes”.