Listen

Chat carries text between objects and avatars nearby or across a region. A script speaks on an integer channel and hears through listeners, which filter what reaches its listen event. Part of the Communications feature.

Concepts

Every message is sent on a channel
- Channel 0 is public chat, seen by people; other channels are only heard by scripts
- DEBUG_CHANNEL shows in the script warning window
Range depends on the function
- Whisper reaches 10 m, say 20 m and shout 100 m from the speaking prim
- llRegionSay reaches the whole region, but not on channel 0
- llRegionSayTo speaks to one avatar or object in the region; on channel 0 to an avatar, only that avatar sees it
- llOwnerSay sends text only to the owner
Messages from scripts are truncated to 1024 bytes
A prim cannot hear itself, but can hear other prims in the same object; use link messages inside an object instead
llListen opens a listener on a channel, optionally filtered by speaker name, key and exact message, and returns a handle
- Only messages that match every filter raise listen, with the channel, name, key and message
- Filters cannot be changed later; a listener on llGetOwner keeps the old owner after a change of owner
Listeners cost the region, so keep them few and narrow
- Pause or resume a listener, or remove it with its handle
- A script can have 65 listeners open; a state change or reset removes them all
- Prefer a filtered, non-zero channel to listening on channel 0

Functions and events

	`llSay(integer channel, string msg)`
	`llRegionSay(integer channel, string msg)`
	`llRegionSayTo(key target, integer channel, string msg)`
	`llOwnerSay(string msg)`
`integer`	`llListen(integer channel, string name, key id, string msg)`
	`llListenControl(integer handle, integer active)`
	`llListenRemove(integer handle)`
`event`	`listen(integer channel, string name, key id, string msg)`

Scripting Details

	`llOwnerSay(string msg)` Sends the chat message msg privately to the object owner (the owner must be currently in the same region for the message to be received).
	`llInstantMessage(key agent, string msg)` Sends an instant message containing msg to the agent identified by their key.
	`llWhisper(integer channel, string msg)` Broadcasts the message msg to all scripts or agents listening on channel within llGetEnv("whisper_range"), which is 10m on most regions. Agents listen on PUBLIC_CHANNEL (0) and DEBUG_CHANNEL (2147483647). All other channels are for script-to-script communication.
	`llSay(integer channel, string msg)` Broadcasts the message msg to all scripts or agents listening on channel within llGetEnv("chat_range"), which is 20m on most regions. Agents listen on PUBLIC_CHANNEL (0) and DEBUG_CHANNEL (2147483647). All other channels are for script-to-script communication.
	`llShout(integer channel, string msg)` Broadcasts the message msg to all scripts or agents listening on channel within llGetEnv("shout_range"), which is 100m on most regions. Agents listen on PUBLIC_CHANNEL (0) and DEBUG_CHANNEL (2147483647). All other channels are for script-to-script communication.
	`llRegionSay(integer channel, string msg)` Broadcasts the message msg to all scripts listening on channel Channel within the region. PUBLIC_CHANNEL (0) cannot be used, so, only scripts can receive the message.
	`llRegionSayTo(key target, integer channel, string msg)` Sends the message msg on Channel privately to the targeted agent or object (if within the region). If target is an agent and channel is non-zero, the message can also be heard by any attachments worn by the avatar.
`integer`	`llListen(integer channel, string name, key id, string msg)` Creates a listener on channel from name and id for msg. Returns an integer listener handle used to control or remove the listener. Empty strings or NULL_KEY filters do not filter on those parameters.
	`llListenControl(integer handle, integer active)` Enables or disables the listener specified by the integer handle. If active is TRUE, the listener is activated; if FALSE, it is deactivated.
	`llListenRemove(integer handle)` Completely removes the listener specified by the integer handle.
`event`	`listen(integer channel, string name, key id, string msg)` 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.

Example

Two objects on a private channel: one sends commands, the other obeys only its owner’s objects.

integer CHANNEL = -731942;

default
{
    state_entry()
    {
        llListen(CHANNEL, "", NULL_KEY, "");
    }

    listen(integer channel, string name, key id, string message)
    {
        if (llGetOwnerKey(id) != llGetOwner()) return;
        if (message == "on") llSetText("On", <0, 1, 0>, 1);
        else if (message == "off") llSetText("", ZERO_VECTOR, 0);
    }
}

Constant groups

Constant groups Channel 3 ChannelNonPublic 2

See also Feature Communications Category Chat SL Wiki Listen SL Wiki LSL ChatPlanned Guide: listeners and channels