On Oct 21, 2013, at 6:53 PM, Vlad <[email protected]> wrote: > Greetings, > > The CTF spec contains a couple of mentions of how one could define a > missing field bitmask: > > "The header is extended in the rare occasions where the information cannot be > represented in the ranges available in the standard event header. They are > also > used in the rare occasions where the data required for a field could not be > collected: the flag corresponding to the missing field within the > missing_fields > array is then set to 1" > > and > > "An example of event-specific event context is to declare a bitmap of missing > fields, only appended after the stream event context if the extended event > header is selected. NR_FIELDS is the number of fields within the event (a > numeric value). > > event { > context = struct { > variant <id> { > struct { } compact; > struct { > uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */ > } extended; > } v; > }; > ... > }" > > Is this capability reflected in the current lttng builds? My understanding so > far is that "missingness" is not part of CTF grammar per se but is rather a > convention (i.e. declaring an array of uint1_t's with a particular name > "missing_fields") -- is this correct? In the extended header example above, > how is a missing_fields slot mapped to its corresponding field -- are the > fields assumed to be ordered, with a slot per field in that ordering?
Ok, lack of response probably means I'd stumbled on an unsupported feature. Cheers, Vlad _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
