Function vips_sys::vips_slist_map4

pub unsafe extern "C" fn vips_slist_map4(
    list: *mut GSList, 
    fn_: VipsSListMap4Fn, 
    a: *mut c_void, 
    b: *mut c_void, 
    c: *mut c_void, 
    d: *mut c_void
) -> *mut c_void