Glom is a filter that accepts event ordered event fragments on stdin and emits event ring items on standard output. Event fragments that represent non physics triggers are just passed through, with the event fragment header stripped off so that they become their initial ring items again.
Any errors glom wants to complain about are emitted to its standard error. It is therefore normally a bad idea to have glom's standard output and standard error pointed to the same sink. Glom's behavior is controlled by command line options that are documented in OPTIONS below.
--nobuildIf this option is present, glom won't attempt to glue together event fragments, but will emit each event fragment as a single vent.
--dt ticks
This mandatory parameter provides the number of
timestamp ticks that define a coincidence interval
when building events. The value of ticks
is ignored but currently necessary when --nobuild
is speicified.
--timestamp-policy policyWhen glom builds output events it builds them with full body headers. This allows the output of glom to be used as an event source for a subsequent higher level event builder. This option determines what is used for the output timestamp in event body headers.
earliest is the default and means the timestamp will be filled in with timestamp from the fragment with the smallest timestamp. latest means that the timestamp comes from the fragment that has the largest timestamp. average means the timestamp is an integerized average of the timstamps of all event fragments in the event.
Glom's output consists of ring items with the following format:
A uint32_t size in bytes of the event. This size is self inclusive
A series of FlatFragment items as defined in the fragment.h header file. The number of fragments is the number required to completely fill the event as determined by the size above.