* John Steele Scott ([email protected]) wrote: > I originally sent this on the 22nd of May, but it looks like it got stuck in > moderation since I'm not subscribed. Reposting via > gmane.comp.sysutils.lttng.devel . . . > > I'm just getting started wiring my up to lttng-ust, and unfortunately > ran into an issue with the first probe I tried, which used a C99 bool > argument.
Fixed by commit: commit 9eb061825ad8ebdf8c22d812eff0232d97d72cd2 Author: Mathieu Desnoyers <[email protected]> Date: Tue Jun 5 13:08:54 2012 -0400 Fix: perform macro expansion on tracepoint signatures The problem can be seen by patching the demo test from lttng-ust as follows: --- a/tests/demo/ust_tests_demo3.h +++ b/tests/demo/ust_tests_demo3.h @@ -22,12 +22,14 @@ extern "C" { * all copies or substantial portions of the Software. */ +#include <stdbool.h> + #include <lttng/tracepoint.h> TRACEPOINT_EVENT(ust_tests_demo3, done, - TP_ARGS(int, value), + TP_ARGS(bool, value), TP_FIELDS( - ctf_integer(int, value, value) + ctf_integer(bool, value, value) ) ) Then when the demo is run with LTTNG_UST_DEBUG=1, a warning is shown, like: liblttng_ust_tracepoint[3315/3315]: Warning: Tracepoint signature mismatch, enabling one or more tracepoints. Ensure that the tracepoint probes prototyp match the application. (in set_tracepoint() at tracepoint.c:310) liblttng_ust_tracepoint[3315/3315]: Warning: Tracepoint "ust_tests_demo3:don signatures: call: "_Bool, value" vs probe: "bool, value". (in set_tracepoint at tracepoint.c:312) It seems that TP_ARGS does not perform preprocessor expansion on the "bool" type spec, while something underneath TP_FIELDS does. And since (at least on this Centos 6.2 box) stdbool.h uses a #define rather than a typedef to make bool equivalent to _Bool, liblttng detects a mismatch. Reported-by: John Steele Scott <[email protected]> Signed-off-by: Mathieu Desnoyers <[email protected]> And tested by commit f121009f677db0f9444e0683e24315eed9c5973d (master branch commits). I'll immediately merge these into stable-2.0. Thanks! Mathieu > > The problem can be seen by patching the demo test from lttng-ust as > follows: > > --- a/tests/demo/ust_tests_demo3.h > +++ b/tests/demo/ust_tests_demo3.h > @@ -22,12 +22,14 @@ extern "C" { > * all copies or substantial portions of the Software. > */ > > +#include <stdbool.h> > + > #include <lttng/tracepoint.h> > > TRACEPOINT_EVENT(ust_tests_demo3, done, > - TP_ARGS(int, value), > + TP_ARGS(bool, value), > TP_FIELDS( > - ctf_integer(int, value, value) > + ctf_integer(bool, value, value) > ) > ) > > Then when the demo is run with LTTNG_UST_DEBUG=1, a warning is shown, > like: > > liblttng_ust_tracepoint[3315/3315]: Warning: Tracepoint signature mismatch, > not enabling one or more tracepoints. Ensure that the tracepoint probes > prototypes match the application. (in set_tracepoint() at tracepoint.c:310) > liblttng_ust_tracepoint[3315/3315]: Warning: Tracepoint > "ust_tests_demo3:done" signatures: call: "_Bool, value" vs probe: "bool, > value". (in set_tracepoint() at tracepoint.c:312) > > It seems that TP_ARGS does not perform preprocessor expansion on the > "bool" type spec, while something underneath TP_FIELDS does. And since > (at least on this Centos 6.2 box) stdbool.h uses a #define rather than a > typedef to make bool equivalent to _Bool, liblttng detects a mismatch. > > So in my tracepoint specifications, I need to remember to use the less > attractive _Bool instead of bool. > > Perhaps it's worth having a special case for this where the trace/probe > signatures are compared? On the other hand, I guess nobody complained > until now? > > cheers, > > John > > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
