MulticastGroup Property

Multicast group to join or leave.

Syntax

 mcast.getMulticastGroup([callback])
 mcast.setMulticastGroup( multicastGroup, [callback])

Default Value

""

Callback

The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).

The callback for the getMulticastGroup([callback]) method is defined as:

function(err, data){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'data' is the value returned by the method.

The callback for the setMulticastGroup([callback]) method is defined as:

function(err){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'err' has 2 properties which hold detailed information:

err.code
err.message

Remarks

This property contains the multicast group to join or leave. Multicast groups are joined by assigning values to this property after the class is activated. More than one group may be joined at the same time. To define which interface to use, the ReceiveInterface property is used.

Determining whether a group is left or joined is done by setting the first letter of MulticastGroup is "-" or "+". The default operation is join.

To remove the class from a multicast group once it is joined, simply assign this groupname (address) to MulticastGroup prefixed by a minus sign "-".

Example (Joining/Leaving Groups)

MCastControl.Active = true
MCastControl.MulticastGroup = "+231.31.31.31"
MCastControl.MulticastGroup = "+232.32.32.32"

MCastControl.MulticastGroup = "-232.32.32.32"
MCastControl.MulticastGroup = "-231.31.31.31"

Data Type

String