listen

event

Event syntax

listen(

integer channel,// Chat channel where the message appeared. Values: Channel
string name,// Name of the sending prim or the legacy name of the sending agent.
key id,// UUID of the sending agent or prim.
string msg// Spoken text string.

) { … }

Triggered when a chat message matching active llListen filters is received on channel. Passes the sender's name and UUID key id, along with the spoken string msg.

Triggered by chat, use llListen to enable and filter

listen(integer channel, string name, key id, string msg)
{

}

Specification

Channel Constant		Description
`DEBUG_CHANNEL`	0x7FFFFFFF	Chat channel reserved for script debugging and error messages, broadcasts to all nearby users.
`PUBLIC_CHANNEL`	0x0	Chat channel that broadcasts to all nearby users. This channel is sometimes referred to as: open chat, local chat and public chat.

Caveats

On state change or script reset all listens are closed automatically.
When an object changes owner any listen registered with llGetOwner will not automatically update itself until the script is reset. The scripter can catch this scenario per the example below.
If a message satisfies the filters of multiple llListens registered by the script, only one event will be raised.
A prim cannot hear/listen to chat it generates.
The location of the listen is not at the listening prim’s location but at the root prim’s location. This is to deter people using child prims for spying over parcel boundaries. Chat generating functions on the other hand generate chat at the calling prim’s location (and not at the root prim’s location).
The above is not true for chat generated by avatars sitting on the same object as the listening prim.

Examples

Example 1

Trivial example to listen to any chat from the object owner and respond once. To reduce lag and avoid spamming surrounding users, it is vastly preferable to listen on channels other than 0 and to trigger the listen event by chatting on an alternative channel such as ‘/5 hello’.

// says beep to owner the first time owner says something in main chat;
integer listen_handle;

default
{
    state_entry()
    {   //Registers the listen to the owner of the object at the moment of the call. This does not automatically update when the owner changes.
        // Change 0 to another positive number to listen for '/5 hello' style of chat.
        listen_handle = llListen(0, "", llGetOwner(), "");
    }

    listen( integer channel, string name, key id, string message )
    {
        llOwnerSay("beep");
        // Stop listening until script is reset
        llListenRemove(listen_handle);
    }

    changed(integer mask)
7 collapsed lines
    {   //Triggered when the object containing this script changes owner.
        if(mask & CHANGED_OWNER)
        {
            llResetScript();   // This will ensure the script listens to the new owner, and doesn't continue listening to the creator.
        }
    }
}

Known issues

From the issue templates included by the wiki article:

SVC-92 (nf): llTargetSay() - region-wide direct communication