From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:39774) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ghEtG-0001FH-Nw for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:31:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ghEtF-0002Nc-9B for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:31:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54990) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ghEtF-0002NQ-0r for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:31:29 -0500 Date: Wed, 9 Jan 2019 14:31:22 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20190109143122.GR3998@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <1547043869-10520-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1547043869-10520-1-git-send-email-thuth@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] configure: Force the C standard to gnu99 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Richard Henderson , pbonzini@redhat.com, peter.maydell@linaro.org, Markus Armbruster On Wed, Jan 09, 2019 at 03:24:29PM +0100, Thomas Huth wrote: > Different versions of GCC and Clang use different versions of the C sta= ndard. > This repeatedly caused problems already, e.g. with duplicated typedefs: >=20 > https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg05829.html >=20 > or with for-loop variable initializers: >=20 > https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg00237.html >=20 > To avoid these problems, we should enforce the C language version to th= e > same level for all compilers. Since our minimum compiler versions is > GCC v4.8, our best option is "gnu99" right now ("gnu17" is not availabl= e > there yet, and "gnu11" is marked as "experimental"). >=20 > Signed-off-by: Thomas Huth > --- > v2: Use gnu99 instead of gnu11 >=20 > configure | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Reviewed-by: Daniel P. Berrang=C3=A9 >=20 > diff --git a/configure b/configure > index b9f34af..721ade7 100755 > --- a/configure > +++ b/configure > @@ -105,7 +105,8 @@ update_cxxflags() { > for arg in $QEMU_CFLAGS; do > case $arg in > -Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|= \ > - -Wold-style-declaration|-Wold-style-definition|-Wredundant= -decls) > + -Wold-style-declaration|-Wold-style-definition|-Wredundant= -decls|\ > + -std=3Dgnu99) IIUC this is to drop -std=3Dgnu99 from CXXFLAGS, so C++ code (only the guest-agent on Win32 IIUC) will use the compiler default still. No worse than what we have today. We could consider also setting a suitable -std for CXXFLAGS too in future though... > ;; > *) > QEMU_CXXFLAGS=3D${QEMU_CXXFLAGS:+$QEMU_CXXFLAGS }$arg > @@ -585,7 +586,7 @@ ARFLAGS=3D"${ARFLAGS-rv}" > # left shift of signed integers is well defined and has the expected > # 2s-complement style results. (Both clang and gcc agree that it > # provides these semantics.) > -QEMU_CFLAGS=3D"-fno-strict-aliasing -fno-common -fwrapv $QEMU_CFLAGS" > +QEMU_CFLAGS=3D"-fno-strict-aliasing -fno-common -fwrapv -std=3Dgnu99 $= QEMU_CFLAGS" > QEMU_CFLAGS=3D"-Wall -Wundef -Wwrite-strings -Wmissing-prototypes $QEM= U_CFLAGS" > QEMU_CFLAGS=3D"-Wstrict-prototypes -Wredundant-decls $QEMU_CFLAGS" > QEMU_CFLAGS=3D"-D_GNU_SOURCE -D_FILE_OFFSET_BITS=3D64 -D_LARGEFILE_SOU= RCE $QEMU_CFLAGS" Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|