The first form of this command places, deletes or lists the script that is associated with properly formed barrier events. If a script is not supplied, the current script is returned. If there is no current script an emtpy string is returned. If a script is supplied it replaces the current complete barrier script. If an empty string is supplied for the new script, no script will be called for future complete barriers.
Complete barrier scripts have appended to them a list of pairs. Each pair contains the source Id of a barrier contributor and the type of barrier event emitted by that source.
The second form of this command performs the same function for incomplete barriers. An incomplete barrier is one for which barrier fragments have not been received from all sources within a timeout period.
Incomplete barrier scripts receives two additional parameters. The first additional parameter is identical to the parameter passed to complete barrier scripts. The second additional parameter is a list of data source ids that did not emit a barrier fragment prior to the barrier timeout.