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Date: Fri, 21 Sep 2012 17:35:19 +0200
From: Wolfgang Grandegger <wg@grandegger.com>
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CC: Steven Rostedt <rostedt@goodmis.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Ingo Molnar <mingo@redhat.com>
Subject: TRACE_EVENT without ARGS
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Hello,

I would like to define trace events for functions without arguments,
e.g. my_yield(). But TRACE_EVENT requires at least one argument to be
defined and I also have not found an example in the kernel sources,
apart from:

  $ cat include/trace/events/xen.h
  ...
  TRACE_EVENT(xen_mmu_flush_tlb,
              TP_PROTO(int x),
              TP_ARGS(x),
              TP_STRUCT__entry(__array(char, x, 0)),
              TP_fast_assign((void)x),
              TP_printk("%s", "")
          );

It uses a dummy argument to work around the problem. Is that the
recommended way to handle such cases?

TIA,

Wolfgang