EVBC::startRingSource

Name

EVBC::startRingSource -- Start a ring fragment source for the event builder.

Synopsis

EVBC::startRingSource source-uri extractor-lib source-id info

DESCRIPTION

Starts a fragment source that gets is data from a ring buffer. For more on ring fragment sources see: ringFragmentSource - a prepackaged client for ringbuffer data sources elsewhere in the documentation. That discussion will provide more information about the meaning of the parameters on the command line.

Note that the fragment source requires the event builder pipeline be up and running. If the event builder pipeline exits, the fragment source will too as soon as it is required to send data to the event builder.

See PARAMETERS below for a brief explanation of the command line parameters, as well as the reference cited above.

PARAMETERS

source-uri

The URI of the ring buffer from which the data will be taken. If the ring is local to the system that ReadoutGUI is running in, you should specify tcp://localhost/ring-name where ring-name is the name of the ring buffer.

extractor-lib

Specifies the file system path to the shared object that contains code that can extract the timestamp from the incoming ring data. Writing and building timestamp extractors. describes how to write timestamp extractors and how to build them in to shared libraries.

source-id

The source id to be associated with the ring buffer. Data flowing to an event builder is placed in several input queues. The input queue selected is described by the source Id which is an integer.

The data from a specific source Id need not all come from the same client, but it must be received by the event builder in strict time order. Data from a specific ring is assumed to constitute data from a single event source.

info

This parameter is arbitrary text that is used to label the data source client in the event builder GUI connection list window. It is intended to allow humans to better understand what each source represents. It is not used by the event builder itself other than to label sources.