Commit 88920427 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt

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.orgReviewed-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
...@@ -22,7 +22,25 @@ ...@@ -22,7 +22,25 @@
* protection, just like TRACE_INCLUDE_FILE. * protection, just like TRACE_INCLUDE_FILE.
*/ */
#undef TRACE_SYSTEM #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. * Notice that this file is not protected like a normal header.
......
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