[lttng-dev] How do you write an argument-less or payload-less kernel tracepoint?

[Thibault, Daniel]

   How do you write an argument-less kernel tracepoint?  I tried:

TRACE_EVENT(hello_nil,
   TP_PROTO(),
   TP_ARGS(),
...
);

and

TRACE_EVENT_NOARGS(hello_nil,
// TP_PROTO(int x),
// TP_ARGS(x),
...
);

   Without success.

   A payload-less tracepoint is possible, but causes a couple of warnings:

make[1]: entrant dans le répertoire « /usr/src/linux-headers-3.2.0-53-virtual »
  CC [M]  /home/daniel/Documents/mymodule/hello.o
In file included from include/trace/ftrace.h:356:0,
                 from include/trace/define_trace.h:86,
                 from include/trace/events/hello.h:151,
                 from /home/daniel/Documents/mymodule/hello.c:5:
include/trace/events/hello.h: In function 'ftrace_define_fields_hello_nil':
include/trace/events/hello.h:130:1: attention : unused variable 'field' [-Wunused-variable]
include/trace/events/hello.h:130:1: attention : 'ret' is used uninitialized in this function [-Wuninitialized]
  Building modules, stage 2.
  MODPOST 1 modules
  LD [M]  /home/daniel/Documents/mymodule/hello.ko
make[1]: quittant le répertoire « /usr/src/linux-headers-3.2.0-53-virtual »

   Is it possible to get rid of the warnings?

Daniel U. Thibault
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