local function main_loop_iter()
    if #rsockets == 0 and #wsockets == 0 then return false end
    local rready, wready, err = socket.select(rsockets, wsockets)
    if err then irc_debug._err(err); return false; end

    for _, sock in base.ipairs(rready) do
        local cb = socket.protect(rcallbacks[sock])
        local ret, err = cb(sock)
        if not ret then
            irc_debug._warn("socket error: " .. err)
            _unregister_socket(sock, 'r')
        end
    end

    for _, sock in base.ipairs(wready) do
        local cb = socket.protect(wcallbacks[sock])
        local ret, err = cb(sock)
        if not ret then
            irc_debug._warn("socket error: " .. err)
            _unregister_socket(sock, 'w')
        end
    end

    return true
end