From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:48972) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ghFCm-0005ve-8m for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:51:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ghFCk-0002Jv-VV for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:51:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45368) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ghFCk-0002Iz-M4 for qemu-devel@nongnu.org; Wed, 09 Jan 2019 09:51:38 -0500 References: <1547043869-10520-1-git-send-email-thuth@redhat.com> <20190109143122.GR3998@redhat.com> From: Thomas Huth Message-ID: <21c94e77-ad1d-3ce2-72cd-fc86f6d619fc@redhat.com> Date: Wed, 9 Jan 2019 15:51:33 +0100 MIME-Version: 1.0 In-Reply-To: <20190109143122.GR3998@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US 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: "=?UTF-8?Q?Daniel_P._Berrang=c3=a9?=" Cc: peter.maydell@linaro.org, pbonzini@redhat.com, qemu-devel@nongnu.org, Markus Armbruster , Richard Henderson On 2019-01-09 15:31, Daniel P. Berrang=C3=A9 wrote: > 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 st= andard. >> This repeatedly caused problems already, e.g. with duplicated typedefs= : >> >> https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg05829.html >> >> or with for-loop variable initializers: >> >> https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg00237.html >> >> To avoid these problems, we should enforce the C language version to t= he >> same level for all compilers. Since our minimum compiler versions is >> GCC v4.8, our best option is "gnu99" right now ("gnu17" is not availab= le >> there yet, and "gnu11" is marked as "experimental"). >> >> Signed-off-by: Thomas Huth >> --- >> v2: Use gnu99 instead of gnu11 >> >> configure | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >=20 > 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|-Wredundan= t-decls) >> + -Wold-style-declaration|-Wold-style-definition|-Wredundan= t-decls|\ >> + -std=3Dgnu99) >=20 > IIUC this is to drop -std=3Dgnu99 from CXXFLAGS, so C++ code (only th= e > guest-agent on Win32 IIUC) will use the compiler default still. We also use it for the capstone disassembler and disas/libvixl. > We could consider also setting a suitable -std for CXXFLAGS too in futu= re > though... Shall I send a v3 with "-std=3Dgnu++98" (which seems to be the only usabl= e option right now), or shall we wait until we really hit a problem with the C++ code? Thomas