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Commit 88920427 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation 

Add documentation about TRACE_SYSTEM needing to be alpha-numeric or with
underscores, and that if it is not, then the use of TRACE_SYSTEM_VAR is
required to make something that is.

An example of this is shown in samples/trace_events/trace-events-sample.h

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org



Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent acd388fd

samples/trace_events/trace-events-sample.h

+19 −1
Original line number Diff line number Diff line
@@ -22,7 +22,25 @@ 
 * protection, just like TRACE_INCLUDE_FILE.

 */

#undef TRACE_SYSTEM

#define TRACE_SYSTEM sample

#define TRACE_SYSTEM sample-trace



/*

 * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric

 * and underscore), although it may start with numbers. If for some

 * reason it is not, you need to add the following lines:

 */

#undef TRACE_SYSTEM_VAR

#define TRACE_SYSTEM_VAR sample_trace

/*

 * But the above is only needed if TRACE_SYSTEM is not alpha-numeric

 * and underscored. By default, TRACE_SYSTEM_VAR will be equal to

 * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if

 * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with

 * only alpha-numeric and underscores.

 *

 * The TRACE_SYSTEM_VAR is only used internally and not visible to

 * user space.

 */



/*

 * Notice that this file is not protected like a normal header.