[lttng-dev] Reading CTF trace using Babeltrace API

[Salman Rafiq]

Dear LTTngers,

I would like to ask few questions related to the API's for reading CTF traces.

1.  Is there any way to read CTF metadata independently, like we have certain API's to read the events.

2. There are certain scopes defined in ctf/events.h like:
	BT_TRACE_PACKET_HEADER          = 0,
	BT_STREAM_PACKET_CONTEXT        = 1,
	BT_STREAM_EVENT_HEADER          = 2,
	BT_STREAM_EVENT_CONTEXT         = 3,
	BT_EVENT_CONTEXT                = 4,
	BT_EVENT_FIELDS                 = 5,

I could not figure out the way to ready the fields 'id' and 'stream_id', for a particular event while iterating through the trace.
Though I can ready the event name using an API and fields using BT_EVENT_FIELDS as a scope.
For e.g. consider the 

event {
	name = sched_migrate_task;
	id = 1;
	stream_id = 0;
	fields := struct {
		integer { size = 8; align = 8; signed = 1; encoding = UTF8; base = 10; } _comm[16];
		integer { size = 32; align = 8; signed = 1; encoding = none; base = 10; } _tid;
		integer { size = 32; align = 8; signed = 1; encoding = none; base = 10; } _prio;
		integer { size = 32; align = 8; signed = 1; encoding = none; base = 10; } _orig_cpu;
		integer { size = 32; align = 8; signed = 1; encoding = none; base = 10; } _dest_cpu;
	};
};


Any help or suggestion related to this issue will be really appreciated.
Thanks!

Regards,
Salman

--
Salman Rafiq
Geschäftsfeld Industrial Communication
Fraunhofer-Institut  für Eingebettete Systeme und Kommunikationstechnik ESK

Hansastraße 32 | 80686 München
Telefon, Fax:  +49 89 547088-356 | +49 89 547088-221
E-Mail:   salman.rafiq at esk.fraunhofer.de
  
Internet: 
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