* John Steele Scott ([email protected]) wrote: > On 20/06/12 03:15, Mathieu Desnoyers wrote: > > * Mathieu Desnoyers ([email protected]) wrote: > >> * John Steele Scott ([email protected]) wrote: > >> > snip snip > >>> The thing I forgot to mention is: okay, I can build now with > >>> -pedantic, but I can't build with "-pedantic -Werror". This > >>> application builds with "--std=c99 -pedantic -Werror" (among many > >>> other flags). I can of course remove -Werror for my tests, but in the > >>> longer term I would like to see lttng-ust enabled in our regular > >>> build, and disabling -Werror for that is not something we want to do. > >>> If I only had to disable it for the trace provider, I could negotiate > >>> that, but disabling it for any module which uses tracepoints is > >>> undesirable. > >>> > >>> I haven't yet looked at how difficult it would be do eliminate these > >>> pedantic warnings. Do you have a feel for what is involved? > >>> Preprocessor tricks warp my mind. :( > >> I don't think we'll want to make the lttng probe module build under > >> --std=c99 -pedandic -Werror, but I think we should focus on making sure > >> the tracepoint part that is built within the application (with > >> TRACEPOINT_CREATE_PROBES _not_ defined) builds fine in --std=c99 > >> -pedantic. > >> > >> Currently, building a simple test program with tracepoints under > >> --std=c99 -pedantic gets me: > >> > >> > >> In file included from ust_tests_hello.h:25:0, > >> from hello.c:34: > >> ../../include/lttng/tracepoint.h: In function ‘__tracepoints__init’: > >> ../../include/lttng/tracepoint.h:261:3: warning: ISO C forbids conversion > >> of object pointer to function pointer type [-pedantic] > >> ../../include/lttng/tracepoint.h:265:3: warning: ISO C forbids conversion > >> of object pointer to function pointer type [-pedantic] > >> ../../include/lttng/tracepoint.h:270:3: warning: ISO C forbids conversion > >> of object pointer to function pointer type [-pedantic] > >> ../../include/lttng/tracepoint.h:274:3: warning: ISO C forbids conversion > >> of object pointer to function pointer type [-pedantic] > >> ../../include/lttng/tracepoint.h:278:3: warning: ISO C forbids conversion > >> of object pointer to function pointer type [-pedantic] > >> > >> ---> see include/lttng/tracepoint.h __tracepoints__init(): > >> ----> This is caused by use of dlsym() to lookup a function pointer from > >> a symbol. dlsym() returns "void *", and we cast it into function > >> pointer type. Ideas on how to make this c99 pedantic compliant are > >> welcome. > > I found this warning discussed in a GCC bug report. Jakub Jelinek's > suggestion at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45289#c6 (load the > result of dlsym into a void *, then memcpy to the function pointer), does > make these go away (using GCC 4.4.6 on Centos 6.2).
Can you check if these can be reproduced with gcc 4.5 or 4.6 ? (without the memcpy trick) The bugzilla entry seems to imply that the warning went away from -pedantic mode at some point. Thanks, Mathieu -- 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
