set_authoritative

set_authoritative — sets the type of a point.

Synopsis

(set_authoritative domain flag)
    

Arguments

domain

The name of the data domain.

flag

A value of 1 indicates that this application is authoritative. A value of 0 indicates that the DataHub instance should be authoritative .

Returns

A message indicating success or error. Please refer to Return Syntax for details.

Description

This command tells the DataHub instance that this application should be considered the authoritative source of data for this data domain. The DataHub instance will keep track of which data points this application has written to it, and will automatically mark those points as being Not Connected quality when the application disconnects. This provides a mechanism for the DataHub instance to provide quality information even if the source application exits unexpectedly.

There should only ever be one authoritative source of data for any data point, though the DataHub instance will not enforce this. If more than one application claims to be authoritative for a data point, that point will be given a Not Connected quality even if another authoritative application is still connected.

The command (set_authoritative domain 0) does NOT mean "turn off authoritative status". It informs the DataHub instance that the application is explicitly non-authoritative, and by extension that DataHub instance should behave as if it is authoritative. Normally this is only meaningful between DataHub instances constructing a tunnel. An application should not send (set_authoritative domain 0) to a DataHub instance. If an application does not want to be authoritative for a data domain, it simply should not send a set_authoritative command.