The engine_send tool can send an event file that associates channels with events. Likewise, the engine_receive tool can output an event file that includes the channel on which an event was received. The event format is the same for both tools:

For example, suppose you want to send Tick events, which contain a string followed by an integer, to the PreProcessing channel. The contents of the .evt file would look like this:

A channel name is optional. In a file being sent with the engine_send tool, you can mix event representations that specify channels with event representations that do not specify channels. Events for which a channel is specified go to only those contexts subscribed to that channel.

The default behavior is that events are sent on the default channel (the empty string) when a channel is not explicitly specified. Events sent on the default channel go to all public contexts. All running Apama queries receive events sent on the default channel. To change the default behavior for events sent by the engine_send tool, you can specify engine_send -c channel. If a channel is not explicitly specified for an event, then it is sent to the channel identified with the -c option . See Sending events to correlators.