近日在一台CentOS6.6的机器上成功安装了QT5.7，但在编写测试程序时，发现无法识别“gun++11”语法，检查当前CentOS6.6的gcc版本为：4.4.7
[root@123 bin]# gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Thread model: posix
gcc version 4.4.7 20120313 (Red Hat 4.4.7-23) (GCC)
4.4.7版本的gcc是不识别c++11语法的。
下面是CentOS6.6将gcc升级至4.8.2的过程：
1. 安装仓库等
#安装仓库
wget http://people.centos.org/tru/devtools-2/devtools-2.repo
mv devtools-2.repo /etc/yum.repos.d
#升级gcc等
yum install devtoolset-2-gcc devtoolset-2-binutils devtoolset-2-gcc-c++新版本的gcc安装在/opt/rh/devtoolset-2/root/ 下。
2. 配置：
#保存以前的gcc
mv /usr/bin/gcc /usr/bin/gcc-4.4.7
mv /usr/bin/g++ /usr/bin/g++-4.4.7
mv /usr/bin/c++ /usr/bin/c++-4.4.7
#为新版本的gcc创建软连接
ln -s /opt/rh/devtoolset-2/root/usr/bin/gcc /usr/bin/gcc
ln -s /opt/rh/devtoolset-2/root/usr/bin/c++ /usr/bin/c++
ln -s /opt/rh/devtoolset-2/root/usr/bin/g++ /usr/bin/g++
3. 检查：确认已经升级到4.8.2版本。
[root@bin]# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/rh/devtoolset-2/root/usr/libexec/gcc/x86_64-redhat-linux/4.8.2/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/opt/rh/devtoolset-2/root/usr --mandir=/opt/rh/devtoolset-2/root/usr/share/man --infodir=/opt/rh/devtoolset-2/root/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --enable-languages=c,c++,fortran,lto --enable-plugin --with-linker-hash-style=gnu --enable-initfini-array --disable-libgcj --with-isl=/dev/shm/home/centos/rpm/BUILD/gcc-4.8.2-20140120/obj-x86_64-redhat-linux/isl-install --with-cloog=/dev/shm/home/centos/rpm/BUILD/gcc-4.8.2-20140120/obj-x86_64-redhat-linux/cloog-install --with-mpc=/dev/shm/home/centos/rpm/BUILD/gcc-4.8.2-20140120/obj-x86_64-redhat-linux/mpc-install --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.2 20140120 (Red Hat 4.8.2-15) (GCC)