net.select()

net.select(socket_array, [timeout])function

Check for network events (readability, writability and errors) on the provided array of Sockets, by updating their corresponding properties Socket.canread, Socket.canwrite, Socket.failed.

Parameters

socket_array

A table containing an array of Sockets to check for network events.

[timeout]

An optional number to indicate the maximum time for select to wait for network events, in microseconds. If that argument is not provided, the function wait until a network event occurs.

Return value

In case of success, returns true.
In case of error, returns false (you can check error message with the net.error property).
If no networking event occured and the time limit expired, returns nil

Example


-- Multi-connection Server example
import net

-- create the server listening Socket
local server = net.Socket("127.0.0.1", 5000)

-- array of clients Sockets
local sockets = {server}
server.disconnected = false

if server:bind() then
  print("Server running on 127.0.0.1:5000")
else
  error("Network error : cannot create the server Socket")
end

while true do
  if net.select(sockets) == false then
    error("Network error : "..net.error)
    break
  end
  
  local alive_sockets = {}
  for client in each(sockets) do
    -- check for readability 
    if client.canread then
      if client == server then
        if server.canread then
          -- check for new connection
          local newclient = server:accept()
          print(newclient.ip.." has connected")
          sockets[#sockets+1] = newclient
        end
      else
        local data = client:recv()
        if data == false then
          print(client.ip.." has disconnected")
          client.disconnected = true
        else
          print(client.ip..": "..tostring(data))
        end
      end			
    end
    -- check for error
    if client.failed then
      if client == server then
        error("fatal network error with server")
      else
        print(client.ip.." has encountered a fatal network error")
        client.disconnected = true
      end
    end
    if not client.disconnected then
      alive_sockets[#alive_sockets+1] = client
    end
  end
  -- keep only connected clients
  sockets = alive_sockets
end