---
title: roDatagramReceiver
slug: develop/rodatagramreceiver
docTags: 
createdAt: 2025-03-11T07:07:18.732Z
---

:::hint{type="danger"}
This object can receive multicast packets, but it doesn't have a way to explicitly join a multicast group. Therefore, this object is not suitable for multicast use. Use [roDatagramSocket](docId\:ZUDWyDM6EHQOv_lVI3Xm-) for multicast receiving.
:::

This object sends *roDatagramEvent* instances to a message port when UDP packets are received on a specified port. The JavaScript equivalent is Node.js Dgram API.

Object Creation: The *roDatagramReceiver* object is created with a `port` parameter, which specifies the port on which to receive UDP packets.

```text
CreateObject("roDatagramReceiver ", port As Integer)
```

## ifUserData

### SetUserData(user\_data As Object)

Sets the user data that will be returned when events are raised.

### GetUserData() As Object

Returns the user data that has previously been set via `SetUserData()`. It will return `Invalid` if no data has been set.

## ifIdentity

### GetIdentity() As Integer

:::hint{type="info"}
The *ifIdentity* interface has been deprecated. We recommend using the *ifUserData* interface instead.
:::

## ifMessagePort

### SetPort(port As roMessagePort)

Posts messages of type *roDatagramEvent* to the attached message port.

This example script listens for UDP packets on port 21075:

```text
receiver = CreateObject("roDatagramReceiver", 21075)
mp = CreateObject("roMessagePort")
receiver.SetPort(mp)
while true
       event = mp.WaitMessage(0)
       if type(event) = "roDatagramEvent" then
             print "Datagram: "; event
       endif
end while
```