Messages in this thread | | | Date | Mon, 2 Sep 2013 18:02:47 +0100 | From | Zoltan Kiss <> | Subject | Re: [PATCH] Documentation/trace: Correcting and extending tracepoint documentation |
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Hi,
I'm not very familiar with the tracing framework, but I will try to comment on your questions.
On 25/08/13 09:59, Rob Landley wrote: > On 08/22/2013 04:49:31 PM, Zoltan Kiss wrote: >> +#if !defined(_TRACE_SUBSYS_H) || defined(TRACE_HEADER_MULTI_READ) >> +#define _TRACE_SUBSYS_H > > But this makes no sense to me: why is it needed? (I.E. why must it be > block copied into each _user_ of tracepoints?) This is to prevent header reinclusion, the second condition makes it possible to include it again from trace/define_trace.h
>> #include <linux/tracepoint.h> >> >> @@ -48,10 +54,16 @@ DECLARE_TRACE(subsys_eventname, >> TP_PROTO(int firstarg, struct task_struct *p), >> TP_ARGS(firstarg, p)); >> >> +#endif /* _TRACE_SUBSYS_H */ >> + >> +/* This part must be outside protection */ >> +#include <trace/define_trace.h> >> + > > Why? (Both why do you need to #include a header outside a multiple > inclusion guard, and why is the additional header needed at all in > _every_ subsystem trace header?) I see only one inclusion guard here, the one above. define_trace.h should take effect at only one place, where CREATE_TRACE_POINTS is defined, to create the tracepoints exactly once. However I don't see as well why it should be outside protection. Maybe because the intentional header reinclusion in it?
Regards,
Zoli
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