Re: [libvirt] [PATCH] build: avoid warnings on older gcc

On 08/15/2012 09:24 AM, Viktor Mihajlovski wrote: > On 08/15/2012 12:42 AM, Eric Blake wrote: >> The previous patch pulled in a newer version of stat-time.h from >> gnulib, which tries to suppress some stupid gcc warnings (see >> <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>) by exploiting >> a feature of newer gcc. But we still aim to compile on RHEL 6.3, >> with gcc 4.4.6 (not to mention even older devel platforms like >> RHEL 5), which fails to build thanks to our development -Werror. >> >> +++ b/m4/virt-compile-warnings.m4 >> @@ -58,6 +58,23 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[ >> # Gnulib's stat-time.h violates this >> dontwarn="$dontwarn -Waggregate-return" >> >> + # Gnulib uses '#pragma GCC diagnostic push' to silence some >> + # warnings, but older gcc doesn't support this. >> + AC_CACHE_VAL([lv_cv_gcc_pragma_push_works], [ I want to use AC_CACHE_CHECK instead of AC_CACHE_VAL anyways, so I'll send a v2. >> + save_CFLAGS=$CFLAGS >> + CFLAGS=-Wunknown-pragmas If you change this line, does it help? CFLAGS='-Wunknown-pragmas -Werror' > Hi Eric, > > I assume this was intended to suppress errors like this here: > > CC libvirt_driver_storage_la-storage_backend.lo > cc1: warnings being treated as errors > In file included from ../../src/storage/storage_backend.c:59: > ../../gnulib/lib/stat-time.h:55: error: no previous prototype for > 'get_stat_atime_ns' [-Wmissing-prototypes] Yep. And I need to mention that in my commit message. > unfortunately, even applying the patch above and rerunning bootstrap, > configure, make didn't help and I'm still getting the errors ... the > interesting thing is that pragma push seems to work... > I am compiling on RHEL6.2, gcc 4.4.6 I'm still investigating why it worked for me. I may have had a stale config.cache interfering with what I posted vs. what I tested earlier. Look for a v2 soon.