# g++-4.7.2 -std=c++11 -c -o /dev/null -xc /dev/null cc1: warning: command line option ‘-std=c++11’ is valid for C++/ObjC++ but not for C [enabled by default] # echo $? 0 # clang++ -std=c++11 -c -o /dev/null -xc /dev/null error: invalid argument '-std=c++11' not allowed with 'C/ObjC' # echo $? 1 # clang++ -std=c++11 -c -o /dev/null -xc++ /dev/null # echo $? 0 -xc option is not good for c++ code. Portage 2.2.0_alpha142 (hardened/linux/amd64/selinux, gcc-4.7.2, glibc-2.16.0, 3.6.3-lto x86_64) ================================================================= System Settings ================================================================= System uname: Linux-3.6.3-lto-x86_64-Intel-R-_Core-TM-2_Quad_CPU_Q9300_@_2.50GHz-with-gentoo-2.2 Timestamp of tree: Sat, 27 Oct 2012 18:15:01 +0000 ld GNU gold (GNU Binutils 2.23) 1.11 ccache version 3.1.8 [disabled] app-shells/bash: 4.2_p37 dev-java/java-config: 2.1.12 dev-lang/python: 2.7.3-r2, 3.2.3-r1, 3.3.0 dev-util/ccache: 3.1.8 dev-util/cmake: 2.8.9-r1 dev-util/pkgconfig: 0.27.1 sys-apps/baselayout: 2.2 sys-apps/openrc: 0.11.2 sys-apps/sandbox: 2.6 sys-devel/autoconf: 2.13, 2.69 sys-devel/automake: 1.11.6, 1.12.4 sys-devel/binutils: 2.23 sys-devel/gcc: 4.6.3, 4.7.2 sys-devel/gcc-config: 1.7.3 sys-devel/libtool: 2.4.2 sys-devel/make: 3.82-r4 sys-kernel/linux-headers: 3.6 (virtual/os-headers) sys-libs/glibc: 2.16.0 Repositories: gentoo systemd hardened-dev custom Installed sets: @local-protected ACCEPT_KEYWORDS="amd64 x86 ~amd64 ~x86" ACCEPT_LICENSE="* -@EULA" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-Wall -Wextra -march=native -pipe -O3 -fno-tree-vectorize" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt /var/bind" CONFIG_PROTECT_MASK="${EPREFIX}/etc/gconf /etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/splash /etc/terminfo" CXXFLAGS="-Wall -Wextra -march=native -pipe -O3 -fno-tree-vectorize" DISTDIR="/usr/local/portage/distfiles" EMERGE_DEFAULT_OPTS="--quiet-build=n" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-logs buildpkg collision-protect config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync multilib-strict news parallel-fetch preserve-libs protect-owned sandbox selinux sesandbox sfperms split-elog split-log strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync webrsync-gpg xattr" FFLAGS="-O2 -pipe" GENTOO_MIRRORS="http://mirrors.163.com/gentoo http://distfiles.gentoo.org" LANG="en_US.UTF-8" LDFLAGS="-Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu -Wl,--icf=safe" LINGUAS="en en_US zh zh_CN" MAKEOPTS="V=1 -j10" PKGDIR="/usr/local/portage/packages-amd64" PORTAGE_BZIP2_COMMAND="lbzip2" PORTAGE_COMPRESS="xz" PORTAGE_COMPRESS_FLAGS="-9ef" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_EXTRA_OPTS="--ipv4" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/var/lib/layman/systemd /var/lib/layman/hardened-development /usr/local/portage" SYNC="rsync://mirrors.ustc.edu.cn/gentoo-portage" USE="X acl alsa amd64 audit bash-completion berkdb bzip2 c++0x cairo caps cli cracklib crypt custom-cflags cxx dbus dri ffmpeg gdbm gmp gnome gpm gtk gtk3 hardened iconv icu ipv6 jit jpeg jpeg2k justify lzma mmx modules mudflap multilib ncurses nls nptl open_perms opengl openmp orc pam pcre png pppd pulseaudio qt4 readline selinux session sse sse2 ssl svg systemd tcpd threads tiff udev unicode urandom vim-syntax xattr xinetd zlib" ALSA_CARDS="hda-intel" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" DRACUT_MODULES="bootchart btrfs caps dmsquash-live gensplash livenet lvm nfs ssh-client syslog systemd" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="en en_US zh zh_CN" PHP_TARGETS="php5-3" PYTHON_TARGETS="python3_2 python2_7" QEMU_SOFTMMU_TARGETS="arm mips64el x86_64" RUBY_TARGETS="ruby18 ruby19" USERLAND="GNU" VIDEO_CARDS="nouveau nvidia" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: CPPFLAGS, CTARGET, INSTALL_MASK, LC_ALL, PORTAGE_BUNZIP2_COMMAND, USE_PYTHON ================================================================= Package Settings ================================================================= sys-devel/gcc-4.6.3 was built with the following: USE="cxx fortran graphite hardened mudflap (multilib) multislot nls nptl openmp (selinux) (-altivec) -bootstrap -build -doc (-fixed-point) -gcj -go -gtk (-libssp) -nocxx -nopie -nossp -objc -objc++ -objc-gc -test -vanilla" CFLAGS="-Wall -Wextra -march=native -pipe -O2" CXXFLAGS="-Wall -Wextra -march=native -pipe -O2" sys-devel/gcc-4.7.2 was built with the following: USE="cxx fortran graphite hardened mudflap (multilib) multislot nls nptl openmp (selinux) (-altivec) -bootstrap -build -doc (-fixed-point) -gcj -go -gtk (-libssp) -nocxx -nopie -nossp -objc -objc++ -objc-gc -test -vanilla" CFLAGS="-Wall -Wextra -march=native -pipe -O2" CXXFLAGS="-Wall -Wextra -march=native -pipe -O2" sys-devel/clang-3.1-r5 was built with the following: USE="(multilib) multitarget static-analyzer -debug -test"
http://sources.gentoo.org/eclass/flag-o-matic.eclass?r1=1.181&r2=1.182